When I received my copy of Lemurs of Madagascar and laid it beside the 1994 and 2006 editions, I could not help but be first struck by its size. Looking at the following ratios of lemur species to page numbers to weight in grams in the three editions, we can see why the size of the third edition is so striking. 1994: 50 species, 356 pp., 325 g; 2006: 71 species, 522 pp., 465 g; 2010: 101 species, 768 pp., 1,390 g. Certainly going from 50 lemur species in 1994 to 101 in 2010 requires a longer guide but the 1 kg it took to get there could prevent even the most avid person from taking this book with them to the field. One wonders, is it worth it? What information contributes to all that weight? And is there a way around it?

A colossal amount of visual and written information contributes to this encyclopaedic volume. It is illustrated by S.D. Nash whose images have improved in nuance, aided by consultation with lemur experts. In combination with photographs we see the lemurs from all angles, and one cannot doubt that with this volume at one’s side, identification in the field could be flawless. This third edition introduces the exciting and novel concept of ‘primate life-listing.’ Adopted from bird ecotourism, this concept is ideal for primates, which are usually easy-to-see, and attractive to tourists because of their close relationship to humans. Thirteen of the world’s authorities on lemurs, primates, genetics and conservation have contributed to the text, providing a definitive guide to current lemur knowledge.

The first 100 pages provide an interesting and painstakingly thorough overview of Madagascar’s ancient geological history, an up-to-date review of the numerous and conflicting theories on how lemurs arrived on Madagascar, and an excellent monograph on the giant subfossil lemurs: a poignant reminder to the threats facing Madagascar’s living fauna. Twenty pages are dedicated to a charming historical account of the study of lemurs, reviewing historical observations of lemurs including my favourite tale of what might have been the last sighting of a now extinct Megaladapis. The major research clusters from various universities are described, and the modern history of how senior researchers and their students came to work on various groups of lemurs is detailed. These sections are illustrated with 68 photographs, lithographs and drawings that are terribly pretty to look at but do not contribute yet to the main goal of a field guide—that is to identify lemurs whilst in the field.

In the next 20 pages the authors face the difficult challenge of summarizing the complex conservation issues facing lemurs and Madagascar. They emphasize Madagascar’s unique biodiversity in a comparative context in terms of plant and vertebrate diversity and specifically in terms of global primate diversity. The text is easy to follow and the terminology is for the non-scientist, so a tourist buying this book can easily grasp the horror of the threats. Unfortunately this serves to make this section even longer.

We then come to the 101 species profiles, beautifully illustrated, with coloured tabs in traditional field guide style, with a simple key in the front cover, making any species easy to locate. Meticulous detail is provided first about each genus, accompanied by excellent distribution maps, the consistent and skilfully drawn iconic ‘Stephen Nash-o-grams,’ as well as mini ethograms for each genus. Each species description is presented in encyclopaedic style, including identification, geographical range, natural history, conservation status, and the all important ‘where to see it.’ These descriptions are accompanied with 1–10 colour photographs of the species, a distribution map, and historical lithographs, many of which are full page. The detail of some species descriptions are so precise that we learn about nuances in dietary differences between two study sites, 2 study years, and contradictory opinions between research teams. Crediting specific research teams and their place of work is a theme throughout that contributes extra wordiness to the text, and will certainly date this book as these researchers move to other institutions. The guide completes with more than 1,000 references, making this a compendium to anyone wanting to read about the latest up-to-date research on lemurs. This is good scientific practice but looking at standard field guides, most of them direct the reader to recommended readings rather than the entire body of literature on a subject.

Conservation International seemed to have the formula right in their 2nd edition of the Lemurs of Madagascar: a comprehensive, informative and beautifully written, handy little book that one would not mind tucking into the front pocket of one’s rucksack. With more lemur species to be described, I think the answer to the 4th edition would be to question the purpose of this book. As a comprehensive guide to lemurs, this edition is a resounding success. It is hugely informative, a useful reference, and one any ecologist would keep at the right hand of their desk until it was tattered and torn from love and use. As a field guide, I think it would keep its pristine condition. On that day the decision is made about what to pack, and looking at that heavy book, remembering what you need in the field is the identifying characters of the lemurs, most people will reach for a Conservation International Pocket Guide or their trusted 2nd edition, and hope for the best that they can identify the 30 new lemur species.