This is the thoroughly revised and updated edition which aims to keep pace with the rapidly increasing information in medical sciences. The text is presented in a simple and lucid manner. It is illustrated with eight colour plates containing 52 figures, computer-drawn figures and photomicrographs. These make the book colourful and the readers can have a better understanding. The book has been divided into eight sections that include:: General bacteriology. Serology/immunology. Parasitology. Systemic bacteriology. Mycology. Virology. Recent advances Spots. Each practical exercise ends with important questions and their answers which will help the student in preparing for theory, practical and viva voce examinations.