If the organizers of the excellent symposium, on which this book is based, had wanted to devise an appropriate dramatic opening they could not have done better than to have the first speaker fail to appear because he was incarcerated in his high security isolation unit caring for a patient suffering from green monkey disease. In his consequently undelivered paper, now published in this book, he understandably dwells a little on the place (both philosophical and physical) of the laboratory in the investigation of highly transmissible infections and this subject characterizes the two themes that run through the chapters of this book: the relative roles of microbiologist and clinician in the investigation and management of infected patients, and the techniques, management and diseases most recently to come under scrutiny. In addition to some airing of the question (which some of us regard as pressing)as to what degree the microbiologist should be clinical and the clinician microbiological, there is welcome attention by the clinical haematologist and immunologist to humoral and cellular factors in infection that are acknowledged to be crucial but relative ly understudied. New looks at old diseases - urinary infections, urethritis and enteritis -and at an old drug, metronidazole, for new indications are all provided by authors who are at the advancing fronts of those sUbjects. The proceedings, completely updated and revised for this publication, seem to me to have been entirely successful in capturing the stimulation and enjoyment of the excellent and instructive symposium.