The new edition of this standard textbook was brought up-to-date in every respect. The results of the rapid advances in bacterial morphology, physiology, genetics, taxonomy, immunology, and physics were correlated with their importance to microbiology. The book covers a wide field in a concise manner. The text is condensed, relating only essentials, but it is most informative. It is recommended to everyone who wishes to teach or to learn the basic facts of bacteriology.