1. This book is written by Major (R) Dr. Saif ud din Saif (M.B;B.S, Master of Public Health - MPH, RMP, RHMP, Professor of Community Medicine) who is qualified in the fields of Allopathic, Homoeopathic and Radiesthesia / Radionics systems of medicine. 2. This book has been especially designed and compiled for the Undergraduate Medical Students, the Internee Officers, the Postgraduate Students and the Pharmacy students. 3. This book is designed to provide a complete comprehensive, current and quick information about the various drug classes and their doses. The classification of various drug groups have been given according to the following characteristics: - (a) Chemical Composition (b) Mechanism of Action (c) Duration of Action (d) Site of Action in the human body (e) Therapeutic Classification (f) Solubility of the drugs (g) Selectivity of the drugs (h) Agnostic Action (i) Antagonistic Action (j) Mode of Usage: Systematic or Topical.