Gavin Pretor-Pinney is on a one-man mission to combat the tyranny of "blue sky thinking." The UK writer is the founder of the Cloud Appreciation Society and the author of "The Cloud Collector's Handbook," a new book celebrating all types of cloudy weather. Fun but serious, the book is a sort of field guide to clouds, teaching readers how to identify various types via juicy photos and informative text.
Pop quiz time! Can you name the type of clouds in each of these photos? Check this New York Times slideshow to test your knowledge.