The two volumes of `General Microbiology` have been written with the objective of providing a basic text in the principles of Microbiology. This is the first attempt by Indian authors to write a text book on General Microbiology. The volumes should be useful for B.Sc., and M.Sc. students offering Microbiology, Biochemistry, Botany and Zoology and for students of Agriculture, Veterinary Science, Medicine, and for students of Agriculture, Veterinary Science, Medicine, Pharmacy, Food Science, Home Sciences and Public Health Engineering. It would have been over-ambitious to attempt both the pure and applied aspects of Microbiology within the limits of space of the two volumes. It was, therefore, decided to stress the basic principles underlying the study of microbiology, and to only briefly indicate the applied aspects.