Somewhere between 1920 and 1950, William Provine notes in an epilogue, ""a consensus concerning the mechanism of evolution appeared among biologists. . . Whatever it is called--evolution, the modern synthesis, the evolutionary synthesis, or twentieth century Darwinism. . . [it was] a comprehensive and compelling view of the mechanism of evolution."" The present volume is no less than an attempt to record how that consensus came about, tapping the memories and interpretations of some of the prime movers as well as latter-day inheritors and historians in the field. The forces to be reconciled were those of the geneticists, other specialists working at the cellular level, and the macrobiologists--those concerned with species, natural selection, taxonomy, paleontology. By the late 1940s, geneticists had taken the lead and laid claim to accomplishing the evolutionary synthesis. Not so, proclaimed Ernst Mayr and C. H. Waddington. In 1974, two workshops were held to address the issue. Mayr was the chairman. Dobzhansky was there. So were Darlington, Provine, Lewontin, DeVore, and such new lights as Stephen Jay Gould, Frank Sulloway, and Robert Trivers. Their retrospective papers, plus contributions from a stellar list of invitees, constitute the text, along with some fascinating biographical appendices. Even a casual reading of the papers points up how disparate were views here and abroad during the first quarter of the century. Many a geneticist was a neo-Lamarckian. Embryologists typically dismissed the genetic material in cells as having no significance for development: after all, the genetic material was the same in all the cells of an animal, but the cells were different. In truth, reading the volume does not clearly explain how synthesis came about--nor even convey exactly what synthesis means. Rather, as Mayr indicates, it shows just how many and how complex were the strands to be woven into synthesis. While the material is all at the professional level, lay readers--and especially students--may find much of this first-hand testimony exciting. For historians and philosophers of science, it is paydirt to be tapped as they debate how pivotal theories form and evolve. What better example than the evolutionary synthesis itself?