Giambattista Bietti, Professor of Ophthalmology at the University of Rome, and Georges H. Werner, virologist from Vitry-sur-Seine, France, have collaborated to produce a timely monograph on the clinical, epidemiologic, therapeutic, and microbiologic aspects of trachoma. Dr. Bietti is a world authority on the disease. He is President of the International Organization Against Trachoma and has published many important papers on all phases of research on trachoma and related diseases. Dr. Werner is well known for his many virologic contributions on this and other diseases. The two authors have reviewed the world literature on trachoma (which is estimated to affect 400 million people) and have made useful analyses on the basis of their own experience.The monograph opens with an historical survey of the microbiology of trachoma. It begins with Halberstaedter's and von Prowazek's demonstration in 1907 of the cytoplasmic inclusions that bear their names, and continues with a complete discussion of the morphologic and biologic properties of the trachoma agent for which the generic names, Bedsonia and Chlamydia, have been proposed.