Altogether, more than 7,150 illustrations are to be found in the two-volumes of this checklist along with 6,431 distribution maps. The artwork is excellent throughout, representing the work of nine artists (Toni Llobet (main artist), Ilian Velikov, Lluís Sogorb, Faansie Peacock, Alex Mascarell, Francesc Jutglar, Blanca Martí, Stephen D. Nash & Jesús Rodríguez-Osorio). The illustrations include 700 of primates and more than 100 of other groups that are new or replacements of paintings featured in the HMW series. Extinct and domesticated species are not illustrated, so I was a little surprised but happy to see paintings of both sexes of Kouprey (an Indochinese bovid). In the 1990s, I organized aerial surveys in remote parts of Cambodia to look for this enigmatic species, without success, and sadly it is very likely extinct (Timmins et al. 2016): Kouprey has not been recorded since the 1960s. Who knows, it’s inclusion may foretell the rediscovery of Kouprey in a remote part of Cambodia, although this does seem exceedingly unlikely.
The species are arranged in a phylogenetic order that represents their evolutionary history, whilst the systematics lean towards a Phylogenetic Species Concept. Volume 1 covers monotremes (echidnas and Platypus) and marsupials (opposums, kangaroos), elephants (with three species now recognised), lemurs, primates and many smaller families of placental mammal, to rodents (hares and rabbits, rats, voles, mice, squirrels). Volume 2 starts with the hedgehogs and gymnures, and includes shrews, moles, bats, whales, ungulates to pangolins and carnivores. One thing that this book decisively demonstrates is that a significant number of the world’s mammal species are small and nocturnal. The rodents, for example, include several very large families, such as the Cricetidae (true hamsters, voles, lemmings and New World rats and mice) with 807 recognised species and the Muridae (true mice and rats, gerbils and relatives) with 851 species, whilst there are 454 species of shrew and an incredible 1,423 species of bat.