Unique pattern of traits, which characterizes the individual, the nature, structure and types of Personality by different Psychiatrists and psychologists. The factors responsible for development of personality of an individual, how the personality will be developed as per age are described in detail, the various techniques used to assess the Personality, Theories of Personality development like Psychoanalytical theory, Psychosexual development, Interpersonal Theory, Hi Eysenck’s theory, Maslow’s theory, Cattell’s trait approach, Gordon W Allport, trait Psychology, Erich Fromm’s view, Carl Jung Analytical theory, Neo – Freudian theories like Karen Horney’s theory, Alfred Adler’s theory, individual Psychology approach, George Kelly’s personal Construct theory, Phenomenological Personality theory by Carl Rogers, Operant Reinforcement theory, Behavioural approaches by Bandura and Walters are explained in detail. Usage of intellectual abilities for handling situation, ability to accomplish tasks is intelligence, its’ nature, meaning, tests used to assess intelligence and measurement of Intelligence Quotient are explained.