Biotechnology is a multidisciplinary subject and needs the knowledge of many areas, like, Botany, Zoology, Cytology, Genetics, Biochemistry, Microbiology, etc., where the microbial cells or cultured plant or animal cells or their products, like antibiotics, enzymes, various organic acids, etc., are produced industrially to be used practically for the welfare of human beings. The book includes 20 chapters and the various topics are written illustratively in a very simple way to make all the undergraduate B. E., B. Tech. and B. Sc. students understand the rather difficult subject easily and comfortably. The valuable suggestions and corrections in this first edition are highly appreciated from the readers.