This is not a book for the faint-hearted as it does require some working knowledge of evolutionary theory. It is however of the highest quality, written by one who unusually had worked with original material and researched the history of the subject. His skill with language helps to conceal the detail and density of his argument but is a paragon of scientific writing at its best. The major weakness is his adherence to the idea that C. Darwin is an important figure in the development of evolutionary thought (he is not), and his reluctance to accept that natural selection is anything other than a minor element in evolutionary processes. These points apart this book should be read by any serious student of evolution.
Gould argues for three pillars that support evolutionary theory: punctuated equilibrium, form and the burden of an organisim's ancestry, and natural selection. Each of these is discussed in detail with clever use of current and historical examples to illustrate each point. Drawing from a broad range of examples, always avioding "just so" stories that fill so many volumes on evolution, he constructs a case that forms the foundations for a viable theory for the 21st century. A magnum opus worthy of a great man.