The Hunsrück Slate, a 400-millionyear-old Devonian formation in the heart of Germany’s Rhineland, is one of the very few places on Earth where large numbers of animals have been preserved nearly intact, including even impressions of their soft tissues. These are creatures of the seafloor, buried by a sudden flow of iron-rich sediment, perhaps from a seismic event or a violent ocean storm. Through processes unique to the chemistry of their time and place, normally perishable body parts have been selectively transformed into the durable mineral pyrite, taking on a golden glow against the dark gray of the slate. In several of the large-format photographs in this album you can see the textured skins of bristle worms, so complete that the fine filaments of their centipede-like appendages are visible. And in another image you see a chimeric creature called Mimetaster hexagonalis, an arthropod with recognizable crablike appendages, but a body that looks like a cross between a bat and a moth. Elsewhere, the multiple arms of a creature called Schizotremites osoleae enmesh its body so profusely that the animal resembles, in the authors’ words, “a rather unruly hairstyle.” The book amply conveys the mysterious vanished world that evolved into the one we inhabit today.