This book is the tale of the mystery of Louis Pasteur and his Library, how he arose from humble beginnings to become the founder of the sciences of microbiology and immunology, how his library was divided and sold to four Americans, none of whom were microbiologists or immunologists but famous in their own rights. The dispersal of la Bibliotheque de Louis Pasteur to the United States, which occurred in the 1960s and 1970s was virtually unknown in France or other countries except for the bibliophiles who purchased and treasured them.In the book, the authors recount the sequence of events that led to the locations of parts of la Bibliotheque in the Huntington Library in San Mateo, California, The University of Alabama in Birmingham, The University of Texas in Austin, and the University of Texas Medical Branch in Galveston. The lives of the bibliophiles are also recounted.Now that la Bibliotheque de Louis Pasteur has been reassembled, it will be possible for scholars in the fields of medical science and history to learn more about the character of Louis Pasteur and how he was able to make the discoveries that became the basis of modern-day microbiology and immunology.Yet many mysteries concerning Pasteur and his Bibliotheque remain to be resolved. For instance, how was la Bibliotheque protected during the German occupation of France during World War II? Indeed, it is hoped that some readers will have information that bears on those unanswered questions.