Underwater Puppies

A few years ago, award-winning animal photographer Seth Casteel became an overnight sensation when his photos of dogs underwater went viral. What followed was a book deal that resulted in the New York Times best-seller Underwater Dogs. Casteel's new book, out Sept. 16, is possibly the only thing cuter than Underwater Dogs: Underwater Puppies.
 Casteel tells NPR's David Greene about using rescue dogs in his photo shoots and about the logistics of photographing.