Previous editions of Mims’ Medical Microbiology have adopted the approach that the interaction between infectious disease and host response is best understood as a give-and-take conflict. The sixth edition continues this tradition, revising the title to Mims’ Medical Microbiology and Immunology to better reflect the subject. Continued recognition of Cedric Mims’ founding contribution to this work is seen not only in the title but also in the foreword to this sixth edition. Ivan Roitt, who played a major role in earlier editions, has relinquished his role as a main author and we gratefully acknowledge his contribution. Overall, this edition benefits from significant revision in multiple areas. The introductory chapters continue to present fundamental principles of infectious agents and host defences but now include the newly recognized importance of the human microbiota. Subsequent chapters present an updated overview of the general principles behind the infectious agent – immune response conflict, followed by a chapter-specific consideration of system-oriented conflict scenarios. Final chapters provide a revised consideration of issues affecting diagnosis and control of the conflict especially centring on newer molecular (especially DNA-sequence-based) approaches. Bibliographic references continue to include current Internet resources. Online access to interactive extras is provided via Elsevier’s STUDENT CONSULT website (www.studentconsult. com) including questions and answers, mostly in USMLE format, the Pathogen Parade (infectious agent) index, and a new Vaccine Parade index. Molecular approaches continue to inform and enlarge our understanding of pathogen–host interaction at a record pace. In this new edition of Mims’ Medical Microbiology and Immunology, we believe the student will find a logical and unified approach to the subject that is readable, exciting, and informative.