The search for effective immunization against pneumonia was a principal avenue of investigation before the advent of The search for effective immunization against pneumonia was a principal avenue of investigation before the advent of antibiotics made such an effort appear unnecessary. Recently, however, the limitations of antibiotic therapy have become increasingly evident, and interest has been renewed in many of the threads of research which have all but lain dormant since the 1930s. In 1978, a pneumococcal vaccine was licensed by the F.D.A., merely as evidence of a renaissance in pneumococcal research which is now taking place. We are pleased to be reissuing two classic volumes which provide a unique repository of data amassed prior to the time when penicillin precluded further exhaustive observation of the unmodified infection. Heffron's Pneumonia is a compilation and analysis of all aspects of pneumococcal disease, including the distribution of pneumococcal types, the pathology of pneumonia, its epidemiology, symptoms, signs, complications, diagnosis, prognosis, and immunology. With a complete cross-reference index and an extensive bibliography, Heffron's book is still the definitive work on pneumococcal infections. White's Biology of Pneumococcus contains the wealth of information acquired in the first six decades following the discovery of the pneumococcus. With a bibliography drawing together some 1593 papers, White's volume is of unquestionable significance as a historical record and the basis for further study.