This hugely influential book, published in 1966 as a 60th birthday tribute to Max Delbrück, is now republished as The Centennial Edition. On first publication, the book was hailed as “[introducing] into the literature of science, for the first time, a self–conscious historical element in which the participants in scientific discovery engage in writing their own chronicle. As such, it is an important document in the history of biology...” (Journal of History of Biology). And in another review it was described as “required reading for every student of experimental biology...[who] will sense the smell and rattle of the laboratory” (Bioscience). The book was a formative influence on many of today’s leading scientists.