Gavin Pretor-Pinney confronts his new book’s major problem right up front. “You might well think,” he writes, “that cloud collecting sounds like a ridiculous idea.”

True, he acknowledges, clouds are ephemeral, “magicked into being” by the atmosphere and constantly changing. And, of course, they cannot actually be gathered up and stored away. But as Mr. Pretor-Pinney sees it, you don’t have to possess something to collect it: “You just have to notice it and record it.”

Hence “The Cloud Collector’s Handbook,” published by Chronicle Books, a serious yet charming field guide to clouds.