The long-awaited third edition is out, with plenty of changes – hopefully, all for the better. The most obvious change is the liberal use of colour, which has improved not only the visual appeal of the book but also its readability. Only a little less obvious is its conversion into a single-author book; how long it will remain so, time alone will show. Still less obvious are the additions to the chapters on cell biology and immunology, which were inevitable in view of the phenomenal advances in these areas. Immunology has been viewed in the book as an integral part of the neuroendocrine network. The growth of psychoneuroimmunology has expanded the scope and implications of homeostatic mechanisms, provided the scientific basis of mind-body relationship, and bridged the gap between modern science and ancient disciplines such as yoga. These advances are both fascinating and intimidating, but only a glimpse can be had in this book. Several other new discoveries have also led to additions scattered throughout the book. The bibliographies have been updated and reorganized to improve their utility. In spite of all these improvements, the size of the book has not been allowed to grow. This has been achieved by deleting relatively less important material.

However, behind these obvious changes is the unchanging commitment to inculcate in the student love for learning by making the process of learning enjoyable. This has now become more important than ever before because physiological knowledge has grown in an exponential manner since the publication of the previous edition. The human genome project has been completed ahead of time, and has given way to functional genomics. To house all the new information, one needs not a book but a library; and to retrieve selectively facts from this vast store of knowledge needs not the human brain but a computer. Therefore medical students and teachers have to shift the focus from remembering to understanding, from total recall of facts to comprehension, analysis, critical evaluation, and application of knowledge. Above all, it has become important that the students preserve their inquisitiveness, discover how to learn, and retain the urge to learn more and more. All these principles are as old as education itself, but so far they have been treated like a luxury; in today's scenario in medical education, they have become a necessity. Understanding Medical Physiology (UMP) is committed to fostering these principles to the extent a textbook can. Any suggestions for doing better towards fulfilling this commitment, and any other suggestions for improving the book, are most welcome.

Although UMP has now become a single-author book, the influence of the previous contributors is inevitably still there. I am grateful to all those who contributed to the previous editions for their indispensable help at a critical juncture in the history of the book. The cover illustration is a product of the skills and hardwork of Dr Ashok Jaryal. The rewritten chapters have been typed by Mr. Satish Sachdeva with meticulous precision. The drudgery of proof reading was shared, besides my wife Lovleen, by Dr. S. Manjunatha, Dr. R.P. Vempati, Ms. Promila Kapoor and Ms. Rooma Basu Ray. The onerous task of preparation of the index could not have been completed without the willing and timely help provided by Dr. Shveta Dhamija, Dr. Ratna Sharma, Dr. S. Manjunatha and Dr. Sanjay Kumar on one hand, and by Mr. Satish Sachdeva, Ms. Premwati, Ms. Pooja Taneja, Ms. Deepali Chugh and Mr. Chandan Singh on the other. I would also like to thank M/s Jaypee Brothers Medical Publishers (P) Ltd. for their cooperation and understanding.

How does this book encourage the faculties of original, critical and creative thinking? Questions and controversies have been raised frequently in the book to jerk and jog the student's mind. The style of presentation prompts the student to try to solve the problem on his own before discovering the solution in the book in a footnote or elsewhere. It may be mentioned that the book is self-contained; it solves every problem that it creates. However, it is expected that the book will inspire the student to create new problems which may require more work. References for further reading are largely limited to monographs and reviews. But cross-references in these secondary sources will lead the student to original articles as and when necessary. Ideally, a book which does not expect the student to accept anything on trust should cite experimental evidence, or at least a reference, for every statement. But limitation of space has made it necessary to restrict experimental evidence only to a very few places where it is specially interesting and instructive. In the above paragraphs I have unwittingly given the most important justification for ‘yet another textbook of physiology’. Most of fm10 the other books available to the medical student fall in one out of two categories. One category includes books that are highly examination-oriented and only serve to strengthen the deeply ingrained habits of uncritical reading. In the other category are excellent books written for the discerning student who has had his earlier education in a developed western country. These books take for granted the student's critical faculties. In India we need a book which has to convert the student. The book has to actively guide the student towards a new learning style with which he is not very familiar. Conversion needs enthusiasm, emotion, and effort. That is why the student may be able to see plenty of these in this book in contrast with the cool and objective prose of present day science.

Besides this intangible respect in which this book differs from its congeners, there are also a few tangible, although minor features unique to this book. Physiology, as it is usually taught, is essentially physiology of the young adult male. There are important ways in which other categories of the population differ from the young adult male. All these differences are not known, but even what is known has an important bearing on treatment of children, women and the elderly, who form the majority of a doctor's patients! An effort has been made to highlight developmental aspects and physiological variations due to age and sex in the present book. Some important topics which usually receive scant attention in an average text on physiology, such as ergonomics, the pineal gland and space physiology, have been given fairly comprehensive treatment in chapters written by specialists in these areas. Finally, some subjects specially relevant to India, such as physiology of yoga, nutritional physiology and environmental physiology, have also been included in a significant way. The origin of many technical terms has been explained wherever it is likely to facilitate understanding. However, the language of the original root (whether Greek or Latin) has not been mentioned because it has no practical significance. Some intellectually stimulating questions and problems follow almost all chapters. The answers and solutions to these are also given in the book, and supplement the information in the text, as do the boxes and footnotes. All these are merely different formats of presentation which have been chosen on the basis of the importance of the information, and to make it more interesting and exciting.

The aims of reading well are to read fast, to read with understanding, and to read critically. To these may be added a fourth very practical requirement: to remember for long what has been read. All these four goals are closely interrelated.

There are a few logical and well established tips for reading fast which are a part of all speed reading courses. To start with, learn to regulate the movement of your eyes. Observe the eyes of one of your friends while he (or she) is reading. You would see that the eyes move slowly in one direction, and then jerk back in the opposite direction. The cycle continues as long as the reading continues. The slow movement is due to the eyes moving along a line on the page. The fast movement brings the eyes back to the beginning of the next line. In fast readers, the slow movement along the line is smooth. But in slow readers, the slow movement is wobbly, which corresponds to the fact that slow readers often keep going back to a word, or a group of words, that they have already read. In short, the first rule of speed reading is to glide the eyes smoothly along a line without going back and forth. This, in turn, has a few prerequisites. First learn to concentrate so that there is no necessity for going back again and again. Secondly, remember that if in spite of concentrating hard, you occasionally fail to register a word or two, you will still get the sense of what you are reading. Thirdly, children are often told not to move the finger along the line they are reading. But experts on reading today not only condone this practice, they actually encourage it. Moving the finger or a pencil along the line being read makes eye movement along the line smooth and swift. To improve still further the speed with which you progress along a line, remember to neither spell nor vocalize the words. It is possible (and normal) to read without looking at every letter separately and clearly. The eyes and the mind often grasp a bunch of letters or fm11 even words at a time, and usually decipher a word upon perceiving only a few key letters. That is why proof reading is a difficult job. Further, it is entirely unnecessary to say the words in your mind (i.e. to vocalize). Vocalizing takes much longer than merely reading the words.

Besides reading fast, it is also important to read with understanding. Increasing the reading speed beyond a certain point is likely to reduce comprehension. But reading fairly fast can be combined with good comprehension by concentration, and by following a few tips. Before you start a chapter, spend a few minutes reflecting over what you already know about the subject, and what more you expect to find out by reading. Then just scan the entire chapter in a few minutes, looking specially at the headings and sub-headings, to get an idea of the concepts discussed in the chapter. Try and form logical connections between the concepts so that what you read in the chapter gets organized in your mind as an interrelated chain of events. Then start reading the chapter from the beginning, word by word, keeping the tips for speed reading in mind. As you read, try to form a mental picture of the events in your mind. For example, if you are reading cardiovascular system, visualise the beating heart or a network of blood vessels in your mind, and try to imagine the effect of variables such as change in venous return, heart rate or vasomotor tone, depending on what you are reading. Or, while reading respiration, try to form a mental impression of the effect of breath holding or deep breathing by actually doing so. Do not hesitate to underline (or upline!) key sentences or clauses. Write in the margins the gist or conclusions or flashes of insight that you sometimes get while reading. The book belongs to you, but it becomes truly your book only when it bears evidence of your interaction with it. If at the end of a portion of the chapter you feel you have in your mind a clear chain of events linked by cause and effect, draw a flow chart depicting it in the book itself, or on a piece of paper which you can stick in the book. As and when you reach a point where a concept has been rounded up, pause for a while and review in your mind what you have understood. Imagine as if you are teaching the subject to somebody else; that is the best way to discover how clear you really are. If you have any doubts, go back to the relevant sentences in the book. It will take you only a few minutes at this stage, but later on even many hours of reading may not be equally effective.

The third goal of good reading is to read critically. This may slow down the speed a bit but it will improve understanding of the subject. Learn to analyse, question and correlate statements. If correlation leads to an inconsistency, investigate it. The investigation may not be immediately fruitful or feasible. In that case note it down in the book for a more opportune moment. With time, critical reading will become a habit, making learning a pleasure. Your intellectual excursions will generally prove the book right. But do not take the printed word for granted. Mistakes creep into books more often than you think.

The fourth goal of good reading, and a very important requirement for the student who has to take an exam, is to retain for as long as possible what has been understood. The tips given above for improving comprehension will also improve retention because the better something is understood, the longer it is retained. However, Tony Buzan has formulated in clear and concrete terms a technique for improving retention which he calls the mind map organic study technique (MMOST).

Before we go into any further details about MMOST, let us understand what a mind map is. A mind map is a ‘new’ concept in preparing personal notes which is based on the way the mind works. Printed material commonly has a linear structure in which a sequence of events or a series of interrelationships is depicted through a major heading on top of the page followed by subheadings under it. But that is not the way the mind works. The mind builds linkages around a main idea rather than under the main idea. In a mind map, we write the main idea in the centre of the page and depict its ramifications around it, somewhat like the branches of a tree. We show the relationships through arrows, geometrical shapes and other symbols, some of which may be invented by the student: it doesn't really matter if nobody else understands what those symbols mean. In a mind map, liberal use is made of coloured pens as an additional code for conveying ideas. In spite of colour, a mind map may appear more messy than conventional notes, but it carries more information in less space and in a format which is more akin to the way we think.

The basic steps involved in MMOST are overview, preview, inview and review.

Overview consists of browsing, somewhat like what you do in a bookshop or in the library before you decide whether to buy or borrow the book. Pay special attention to headings, indents, summaries, words in bold type or italics, tables and figures. After getting a hang of what the subject is, jot down what you already fm12 know about the subject in the form of a mind map. Decide on the time you will spend studying the subject, and the amount you will complete. In other words, set your goals and the resources (in this case, time is the major resource) you will employ to reach them.

Preview is akin to scanning. With an active mind, select and reject what you read. Concentrate on the beginnings and ends of paragraphs, which are the portions which usually provide the most valuable information. Have no sense of guilt about skipping passages. Treat a book like a lecture: accept, ignore and criticise as appropriate.

Inview is a more detailed reading than preview, but you are authorized to skip even at this stage. Learning something is like completing a jigsaw puzzle. It is sometimes worthwhile to forget about a missing piece for some time instead of getting stuck. A difficult passage is likely to get easier after you have read subsequent passages or another section. This is also a good stage for making `notes’. Notes should be on the book as well as on large sheets of paper. On the book, underline and write freely as suggested earlier. On the large sheets of paper, prepare mind maps, either by adding on to the maps prepared at the overview stage, or by making new ones, as appropriate.

Divide the study time into 20-50 minute sections. Take a break between each section: it is cost effective.

Review is an important step, and a continuing exericse. One review is required more or less immediately after the reading session to examine for yourself how much you know, and to have a second look at the marked, important portions. But reviews are required after that also, because it has been observed that within 24 hours of a one-hour learning period, more than 80 percent of the learnt material is forgotten. Tony Buzan recommends the following schedule for reviewing: a 10-minute review 10 minute after the learning session, and three shorter 2-5 minute reviews 24 hours, 1 week and 1 month after the learning session. These four reviews would fix the material in long-term memory, and help its retention for a very long time. You might ask how one would remember to review a subject one week or one month later. One way is to maintain a diary: a habit which would be useful in many other ways too throughout life. Suppose you have learnt ‘Oxygen transport’ on 9th October, make an entry ‘Review oxygen transport’ in your diary on 10th October, 16th October and 9th November. It goes without saying that the system will work only if you remember to consult the diary everyday.

Although MMOST may appear to be a rigid technique, one should only grasp its general principles and put them into practice. Details of the technique may be altered depending on the subject being studied and other circumstances. No technique should be allowed to interfere with the intensely personal and pleasurable experience of learning. Reducing the technique to a rigid routine can make the process of studying boring and burdensome.

They are uneducational because they place an implicit limit on what the student may learn by saying indirectly that knowing anything beyond the SLOs is unlikely to be rewarded. They also encourage the student to turn around and say that the teacher cannot ask a particular question because it is not a part of the SLOs. I find such a stand ridiculous, specially in an advanced course of learning, and that too in medicine. When the student becomes a doctor, would he be able to tell a patient that he would not treat him because a particular symptom of his was not a part of his SLOs? What is expected of a doctor in such a situation is to jog his mind, use some logic, and reach some reasonable conclusion. The conclusion may not be entirely right, but if the doctor has applied his mind properly, he will not commit a blunder. What better preparation can the student have to acquire this mental smartness than to face somewhat unexpected questions in the examination with studied equanimity? When a student is asked a question, the usual tendency is to try and give the right answer as quickly as possible. I always tell my students to interpose between the question and the answer one more step: thinking. If you take the time to think, you will not be very much off the mark even when you answer a fm13 question which you do not know. If you jump to the answer without thinking, you may give an absurd answer even to a question which you know.

SLOs are impractical because teachers cannot keep thinking of the SLOs if they have to give a lucid and interesting lecture, and students seldom realise all the objectives laid down but still pass the exams. No wonder, neither the teachers nor the students generally consult published documents on SLOs while teaching or studying. However, on the basis of having taught and examined students for more than twenty years, I can say quite confidently that any MBBS student who masters the essence of this book will find his physiology examiners highly satisfied.

Large chunks of the manuscript were typed by Ms Jatinder Kaur willingly and cheerfully. The index was typed promptly and meticulously by Ms Babita Shreshtha.

The diagrams have been brought alive by the artists: Ms Jigeesha Pasricha, Ms Sunita Gadde and Mr RK Majumdar.

My wife, Lovleen, and daughter, Arpita, cooperated whole heartedly during crucial phases of preparation of the manuscript and provided invaluable support throughout the long years which it took to complete the project.

I am grateful to all the publishers who have allowed the use of illustrations from their publications in this book. Their courtesy has been acknowledged individually at appropriate places. However, Messrs Oxford University Press deserve a special word of thanks for granting permission to reproduce, with minor modifications, material which I had earlier contributed to one of their publications. The material appears in this book as Chapter 6.12.

The publishers, Messrs Jaypee Brothers, tolerated my delays and eccentricities patiently and gracefully, and did not add any further delays to the project. Last but not least, I am grateful to the National Book Trust for providing a subsidy under their Core Books in Medicine Programme which has made it possible to bring down the cost of the book considerably.

It is different because it seeks to educate the medical student in physiology, leading him or her from a state of diffidence and uncertainty, through pathways of insight and interpretation, to a knowledge of the details of physiological science to be applied to a medical career. So many other textbooks are instruction manuals, assuming, usually unrealistically, that students already have an understanding of the principles and concepts of physiology on which to construct a soundly-based knowledge of medical physiology. Dr Bijlani implies that an initial lack of perceptive background may be especially common in India but, alas, it is also very frequent in the western world. Far too many medical students learn in order to pass exams and to qualify; this book will educate them and make them better doctors as a result.

The book is also unusual because Dr Bijlani in his preface urges students to underline parts of the text, to make marginal notes, and even to say where they think the text may be wrong. How many authors encourage desecration of their work? But it is an important point. I learnt years ago that students who came to me with a text full of underlinings, crossings out and question marks were the ones who really read and tried to understand what they had read. A blank unmarked text can imply a blank and unremarkable mind.

One of the fascinations of this book are the insets, blocked out sections of historical, anecdotal and clinical material which, while they may not help the student to pass exams, are lightening flashes of illumination. Please, Dr Bijlani, in the next edition can we have more of these?

These differences compared with other textbooks of physiology are commendable, and make the book better than most texts with which I am familiar. The questions and answers at the end of each chapter demand understanding and not merely factual knowledge. All the illustrations have been drawn by the authors themselves, and have both a uniformity and a refreshing and unconventional appearance that make them easy on the eye. The book is easy reading, because of its conversational and didactic style, and the length, almost 1000 pages of double columns, is never oppressive. Dr Bijlani has written two thirds of the book himself, and has chosen for the other sections authors who agree with his philosophy and approach.

In this preface Dr Bijlani tells a story about JBS Haldane, a great scientist and a great lover of India. Many years ago I wrote to Haldane in India, asking for a reference for an Indian doctor applying for a job with me. Haldane sent me a five page hand-written letter. The first sentence read: “He is a very able man, you should take him”. The rest of the letter was about his philosophy of medical education and his admiration for the Indian attitude to learning and life.

My advice to a potential reader of the textbook is simple: “The book is excellent and you should get it”. Like Haldane's letter the book has the right balance. If you absorb it you will gain far more than a knowledge of physiology, you will discover what physiology is all about and how Indian physiologists can illuminate understanding of the subject for both students and teachers. The book is an education, and there cannot be higher praise.