According to its back cover, the book Bats is intended to provide “a guided tour of the nocturnal world of bats,” illustrating the major aspects of bat diversity, biology, ecology, and conservation, with examples of species from around the world. Developed and published in the United Kingdom by the British Natural History Museum, Bats is written for a general audience. Author Phil Richardson was a career science teacher and is a dedicated bat ecologist who has been working to promote bat conservation and research in the United Kingdom for more than 30 years. Had I received this book to review some 15 years ago, I would have considered it a fairly enjoyable introduction to bat families and bat natural history. I might have expressed some concern about the technical inaccuracies, inconsistencies, and generalizations that are scattered throughout the volume, but I would have acknowledged the book's nice illustrations and its wealth of color photographs, and complimented the author's comprehensive treatment of the material and his engaging style of writing. Today, however, I am immediately aware that much of the opening chapter, “Bat evolution and biology,” is at least 10 years out of date and does not reflect current evidence and consensus on key elements of bat evolutionary history and classification.

Richardson provides basic summaries of the morphology and ecology of most of the bat families in chapters 3–5, and he highlights research findings relevant to individual species, but I had lost faith in the content of this book by page 9. To start, the author finds it likely that Old World fruit bats (Pteropodidae) “evolved along a very different path from the insectivorous bats, one that branched off from the primates” (p. 7). This statement refers to the debate over whether bats are monophyletic (all living species ultimately having descended from a common ancestor) or diphyletic (having two independent origins). This ‘flying primate hypothesis” was based primarily on morphological differences between Old World fruit bats and all other bats and was rigorously championed by Jack Pettigrew in the late 1980s and early 1990s. Counter-arguments raged for a while, but ultimately, several multigene molecular phylogenies—notably, those produced by Emma Teeling and colleagues beginning in 2001—offered no evidence for diphyly in bats, and today, the vast majority of evolutionary biologists accept the monophyletic origin of bats. For those interested in tracking this debate, John Altringham gave a nice summary in his second edition of Bats: From Evolution to Conservation (Oxford University Press, 2011).

Furthermore, the first box in chapter 1 covers the classification of bats, which is used to organize much of the material in subsequent chapters. Chapter 3 covers “megabats,” and chapters 4 and 5 review several of the larger “microbat” families, reflecting the previous division of the order Chiroptera into two suborders—the Megachiroptera, which consisted of only the family Pteropodidae, and the Microchiroptera, which contained all other families. However, evidence that this traditional classification does not reflect evolutionary history began to emerge, primarily from molecular analyses exploring the “flying primate hypothesis,” some 14 years ago, with a flurry of papers culminating in a Science publication in 2005 from Emma Teeling and colleagues. Their multigene phylogeny generated a very different evolutionary tree, one that has since been universally adopted by the research community and has dissolved the Megachiroptera—Microchiroptera division for good.

The current evolutionary tree identifies two major lineages: the suborders Yinpterochiroptera and Yangochiroptera. Critically, the Yinpterochiroptera unites the plant-visiting Pteropodidae (the old “megabat” group) with five insectivorous “microbat” families grouped into the superfamily Rhinolophoidea. It seems likely that this group evolved in Asia, and its range is currently restricted to the Old World. The remaining “microbat” families fall into three superfamilies that make up the Yangochiroptera, the geographical origins of which are unclear but which currently has a global distribution.

The last 15 years have been a very exciting and transformational time in the study of bat evolution; there has even been progress in the quest to find a “missing link” in the fossil record with the discovery of the Onychonycteris finneyi from the Green River Formation in Wyoming. Limb proportions of this primitive bat from the Early Eocene were between those of nonflying mammals and known bats, and it had claws on all fingers. This intriguing find has fueled the ongoing debate as to whether flight in bats evolved before or after echolocation or whether the two traits coevolved. Richardson's volume fails to reflect the excitement and the findings of this last decade and provides an outdated classification system to organize what constitutes the core of the book. In addition, minor errors in the material that falls within my own specific expertise only reinforce my lack of confidence in the text (there are approximately 330 species of bat in Southeast Asia, not 100) and leave me questioning the accuracy of the other material in the book, with which I am less familiar. Books written for a general audience often do not provide citations to support their statements, so it is all the more essential that they present both accurate and contemporary findings.

The final chapter of Bats is focused on bat conservation, and I was disappointed to find this to be a rather cursory and outdated treatment of the topic, in which the substantial global conservation research efforts of the last decade, as well as the emergence of new threats to species, were omitted. No mention is made of the substantial mortality rate of bats from wind-turbine farms; no attempts are given to explain and allay fears about the role of bats in emerging infectious diseases, such as SARS, Nipah virus, and Ebola, and the transmission of the rabies virus. Moreover, there is a growing movement among many bat researchers that work with the public to ensure that images of hand-held bats are limited to those in which the holder is wearing gloves. Although the incidence of bat-borne viruses is very low in most countries—and with most species, the use of gloves clearly reduces the risk of being bitten and the chances of transmission. I suspect that the photograph (p. 117) of a child holding, in her ungloved hand, a Daubenton's bat—the only species in the United Kingdom found with live European Bat Lyssavirus—will not sit well with many practitioners.

In summary, this book is a missed opportunity. It is clear that the author stopped gathering and reviewing content at least a decade ago. Perhaps this might matter less if recent research were simply refining and augmenting existing knowledge, but in the past 15 years, major changes have developed in our understanding of bat evolutionary history. New threats to bat populations have emerged, and existing threats have worsened. A book with such broad appeal should present the most current body of knowledge possible at the time of publication, particularly if it is intended for a general audience. Failure to do so does a disservice to the interested public.