In this chapter different types of techniques of preparing root canal for endodontic completion is described with the help of 26 figures. Biomechanical preparation, instruments required, like; exploring, extirpating, engaging, filling instruments etc. are detailed. How the hand instruments are numbered, rules governing biomechanical instrumentation (described in 11 points), rules for maintenance of root canal instruments (described in 6 points), is all explained. Difficulties encountered during biomechanical preparation of the root canal like; accidental perforation, broken instruments in the canal, how to remove broken instruments from the canal (described in 8 points), what is chemical preparation of root canal, what are chelating agents, are all discussed in detail. How to locate the “apex” is given in chart-form with figures of each technique. Some 6 methods are described with complete details. Electronic apex locators of resistance, impedance and radio-frequency type are also described.