My Octopus Teacher might have alerted us to the idea of a novel alien intelligence beneath the waves, but nothing can prepare you for the profound diversity and unconventional beauty of octopuses, seahorses, and jellyfish seen through the lens of National Geographic photographer David Liittschwager. On facts alone, the animals astound. Sixty-five percent of an octopus’s neurons are outside their brain, in their arms. Female seahorses impregnate males. One species of jellyfish can reverse aging and start its life cycle anew. And yet, Liittschwager’s photos are even more mesmerizing than the facts. Created with a pair of condenser lenses against mostly white backgrounds, they reveal these critters in granular detail, showing an infinitude of texture and pattern, and you can’t help but ponder the consciousnesses staring back. (Except for the jellies, which have no eyes. Or brain. Or blood.) It is a marvel of a book.