The book has been designed for students preparing for IAS, IFS, IES, IES/iss, SCRA, CMS, CPF, CDS, NDA/NA, SSC, PSC, and other competitive examinations. The approach is comprehensive and covers almost every prescribed subject incorporating the fundamental principles and facts as well as the finer details not easily available in a single source. It has been compiled after consulting various encyclopaedias, reference manuals, standard textbooks, dictionaries, newspapers, and magazines and other authentic sources. It has been written in simple language and lucid style with revision exercises to reinforce the reader understanding of each topic. Where subject matter overlaps, Duplication of Matter has been avoided by providing cross-references to facilitate easy access to the required information. There are multiple choice questions of a wide range, designed to test and enhance awareness, by forming information units on their own.