In 1970, the first edition of the Manual of Clinical Microbiology (MCM) was published by the American Society for Microbiology. Nineteen editors and 98 authors presented, in 77 chapters and 727 pages of text, a state-of-the-art description of clinical microbiology...The Manual has now expanded to 130 chapters and 1,773 pages of text. Despite the many changes in clinical microbiology, the fundamental philosophy of the Manual has remained the same...The Manual "is intended to guide clinical microbiologists in the selection, performance, and interpretation of laboratory procedures for diagnostic and therapeutic applications. It is a reference source defining not only what is done in clincial microbiology laboratories but also what these activities signify."...With many changes in editors, authors, subject matter, and presentation, we believe that we have maintained the tradition of the Manual of Clinical Microbiology and improved from the foundation of the last six editions. We hope that the readership will find this text useful, accurate, and timely.