Raymond Cowles grew up in South Africa, ended up at UCLA, and more or less invented the study of how cold-blooded animals manage their own body heat — the reason we know a lizard is running a schedule all day, moving between sun and shade to hold its temperature. This is the book he left behind, finished by Elna Bakker after he died and published in 1977. It’s field notes more than argument: rattlesnakes and sidewinders, horned lizards squirting blood, the rosy boa, black widows, Colorado River toads, condors, the Imperial Valley, camps and canyons and what happens after a desert storm. He keeps circling one thing he noticed late — that desert animals need open ground, and that the space itself is a requirement, not a backdrop. There’s a chapter on human population that he was writing about decades before anybody wanted to hear it.