In this chapter the objects of ideal root canal preparation, Eberly’s principle, importance of irrigants, proper use of needle and syringe for irrigation of root canal, are all described. Cleaning and shaping of the root canal system by “Step-back” and “Crown-down” techniques are also compared. Crown-down root canal preparation technology is described in detail. Use of NITI instruments, importance of irrigation, recapitulation with hand file K-10 or K-15, is well stressed. Engine driven canal preparation instruments along with their brand names and the company manufacturing them is also covered. Color code of “Tulsa pro-files” and “Maillefer’s pro-files are given in table-form for better, quicker and easy identification. Recent emerging all facts about “Cleaning and Shaping” of root canal system by “Crown-down” technology is also described in detail (described in 23 points).