Some of the pieces were written for popular magazines such as Natural History and The Florida Naturalist, while others were review papers or book reviews in scholarly journals and books. They have been substantially reworked, with some updating, the addition of a brief introduction, and the removal of details, diagrams and references.
Two essays describe early applications of protein electrophoresis, exploring the genetics of speciation and testing the "neutral" theory of evolution. Several essays present applications of mitochondrial DNA sequencing, in taxonomy and phylogenetics, for the study of population structures within species, and in exploring unisexual taxa. And there are essays on speciation and species concepts, on age, sex and DNA repair, and on reproductive strategies in fish.
A number of the essays cover conservation issues: early applications of molecular analysis to pocket gophers and sea turtles, the "Biosphere 2" project, and an American perspective on Australian biodiversity. Two of the essays look at the role of metaphors, in genomics and in evolutionary biology more broadly. And "The Best and Worst of Times for Evolutionary Biology" considers the future of the discipline and some of its social implications.
The essays are presented in chronological order, which only occasionally seems awkward. Chapter five, a popular introduction to phylogenetic applications of mitochondrial DNA, could surely have come before chapter four, a more technical paper covering similar material, if only to save the reader having to look up "catadromous". The effect is to give a feel for how the field has changed over the last thirty years, and for some of the key ideas that have driven it. So one audience for On Evolution will be students, who will benefit from its historical perspective on the development of the field.
As an attempt to rework scientific papers for a broader audience, On Evolution resembles Avise's earlier Evolutionary Pathways. Where the pieces in that were all similar in presentation, however, On Evolution is awkwardly balanced. Some of its essays could be printed in a newspaper and many could be enjoyed by any reader of popular science. Most assume a bit of background biology — Avise doesn't stop to explain concepts such as "electrophoresis" and "monophyletic", for example. And some will make little sense to those outside the field: "Cladists in Wonderland", for example, is perhaps the most entertaining piece in the collection, but it won't make much sense to anyone unfamiliar with the debate over species concepts.
Reworking scientific publications for a broader audience is a valuable undertaking and the pieces in On Evolution are fine examples. But a book is not the ideal form for such a diverse collection. This is one case where I think some kind of web publication would make most sense, allowing those interested in specific topics to find just those pieces that interest them and that are pitched at an appropriate level.
Note: this review was commissioned by and first appeared in Systematic Biology.