Let's say you're a photographer who strikes it big with a whimsical book featuring dozens of images of dogs splashing around underwater (aptly titled Underwater Dogs).

Where do you go from there?

If you're Seth Casteel, you follow up with an even more adorable collection. Underwater Puppies (Little, Brown and Company) is on sale now, and animal lovers can flip through page after page of pups exploring the life aquatic.

Casteel worked with the puppies on their paddling skills before letting them float solo, making sure they were comfortable in the water. Once beneath the surface, their captivating personalities came through. Whether you see them as bold, nervous, camera-shy, or just plain silly, all of the furry models are absolutely "d'aww"-worthy.

Prepare to swoon with this selection of images from Casteel's new book:

Ruger | (Seth Casteel)

Pringles and Pickme | (Seth Casteel)

Reason | (Seth Casteel)

Monty | (Seth Casteel)

Rolley | (Seth Casteel)

Popsicle | (Seth Casteel)

Iggy | (Seth Casteel)

Ava | (Seth Casteel)

Corey | (Seth Casteel)

Ginger | (Seth Casteel)

**Buy Casteel's book here or here**