That’s because photographer Seth Casteel — the man behind the NY Times bestseller and viral sensation Underwater Dogs — is back with another installment of his series that promises to be even more adorable than the first.

How could this possibly be, you ask? Well, for this second iteration, Casteel taught 1,500 puppies how to swim, making the resulting photo book so squee-inducing you might just explode from all the cuteness.

The 72 underwater photographs Casteel captured over the course of these swim lessons have been compiled into the book Underwater Puppies, which is already available at Barnes & Noble for $13.65.

As with Underwater Dogs, Casteel captures that magical moment that the pups first enter the water, all excitement, enthusiasm, and in some cases reticence or wide-eyed surprise. It really is just about guaranteed to put a smile on your face:

Many of the puppies like Corey here, were from rescue shelters and had not experienced swimming or jumping into a pool.

“Popsicle” taking the plunge for the first time.