The contents of the future are the contents of a cloud.So begins translator David Larsen's introduction for the Book of Rain, the earliest known catalogue of Arabic weather-words, by early Arabic linguist Abū Zayd al-Anṣārī. In Larsen's translation, Abū Zayd's lexicography of rain is simultaneously an academic, archival, and poetic pursuit.After the fashion of Larsen's award-winning translation of Names of the Lion, these rich, extensive lists provide detailed descriptions of specific kinds of rainfall, including al-tahtān, or "The Outpour," a kind of continual rain, or al-waṭfā', or "The Beetle-Brow" which is a "briskly-flowing rain that is counted among the continual rains, whether it is of long or short falling." Here, we are provided language for frosts, dews, thunder, lightning, clouds, and, of course, the various and plentiful words for waters. Coupled with Larsen's introduction, the Book of Rain is a source of endless interdisciplinary inquiry which will continue to fascinate readers for centuries to come.