The Book of Barely Imagined Beings: a 21st-Century Bestiary, By Caspar Henderson. Granta, £20

The first thing that strikes the reader on picking up Caspar Henderson's Book of Barely Imagined Beings is the care that has gone into its production. Once past the cover (embossed in gold), the foil-blocked spine and illustrated end-papers, the most innovative note is struck by the footnotes that run parallel to the main text, colour-matched to highlighted words.

The medium is at least part of the message. The author, the design suggests, intends to combine the fantastical content and omnivorous curiosity of a medieval bestiary with the latest scientific research. And so he does. Henderson takes his title from a work by Jorge Luis Borges, a fictional anthology of outlandish beasts. Falling asleep in a field after reading it, alongside troubling articles on ecological and other disasters, he wakes with the compulsion to write a similar book, but based on real creatures. By making a selection, one animal for each letter, from Axolotl to Zebra-Fish, via "H" for Human Being, he can demonstrate not only the staggering fecundity of evolution but the fragility of the eco-system that supports such diversity.

Two-thirds of his chapters are devoted to sea-dwellers. The previously unsearchable depths of the ocean are yielding up new species even as its upper reaches are polluted and over-fished. We have entered a new epoch, the Anthropocene, in which humans are the largest single influence on the Earth system. By "calling up" these exotic species, Henderson hopes to prompt a sense of responsibility as well as wonder. Who could resist the charms of the brownsnout spookfish, its bi-focal eyes kitted out with internal mirrors? And who would not be chilled to know that there are a third fewer wild animals on our planet than a mere 40 years ago?

At times, the reader is in danger of being submerged in a torrent of information only loosely connected. Yet Henderson's extended paean to nature's creativity leaves us with a sense of unfinished business rather than inevitable doom.