Colton, 11 months – Casteel's photos of babies and animals have been featured in The New York Times, National Geographic Magazine, The Washington Post and the "Today" show.
Michael G., 12 months – Casteel partnered with swimming schools and organizations that promote child water safety to arrange the photo shoots for "Underwater Babies."
Ayla, 7 months – "Chubby-cheeked, curious, and mischievous, these tiny swimmers remind us all of the joy of discovery -- and the irresistible beauty of babies," the book's jacket proclaims.
Zelda Mae, 7 months – The photographer hopes to bring more awareness to water safety education for children with the book.
Warren, 11 months – "I strongly advise parents to consider all of the amazing benefits of infant swimming lessons and to choose a program that is right for them and their child. Participation in formal swimming lessons can reduce the risk of drowning by 88% for children under age 5," Casteel writes in the book's introduction.
Emerson, 7 months – The babies' parents were present for the photo shoots, along with water safety professionals, to ensure the children's safety and comfort.
Zoe, 5 months – Casteel sought to capture in his photographs the unique facial expressions of each child as they encountered the water.
Valentina, 9 months – Some of the babies wear a simple swimming diaper for their photographs while others don elaborate swimsuits, bathing caps and goggles. Here, Valentina holds a colorful prop.
Khyleigh, 9 months – Formerly an ad man, Casteel's career photographing underwater started when a dog he was taking photos of jumped into a pool unexpectedly.
Michael R., 4.5 months – After Casteel's dog photos were featured on Reddit, they went viral, and a new career was born. His photo books include "Underwater Dogs," "Underwater Puppies" and now "Underwater Babies."