This book belongs in the hands of every laboratory person who deals with mycobacteria. I addition, it will be very helpful to the tuberculosis specialist who has an interest in the immunologic aspects of this disease. The author intends to bring the reader up to date on the developments in the field of tuberculosis since Rich's classic text on the pathogenesis of tuberculosis was published. He succeeds in this purpose in an admirable way. IfRich's book is the bible of the tuberculosis specialist, then Youman has added the new testament.