This fourth edition of this microbiology text has been revised and contains a new review section at the end of each chapter consisting of crosswork puzzles, matching and fill-in-the-blank questions. Answers to the questions for thought and discussion are provided in a new appendix. Using historical anecdotes and case studies, this book's content is presented in a student-oriented manner. There are mid-chapter reviews; the margins are used for pronounciations, definitions and drawings; key words and phrases are in bold-face.