One of @NatGeo's most popular nature photographers shares 200 breathtaking images -- and the stories behind them -- from a wide swath of wild ocean locales around the globe.

From gregarious gray whales plying the waters of Baja California to acrobatic manta rays in the Maldives and parading penguins in Antarctica, National Geographic photographer Thomas Peschak has spent a lifetime documenting the beauty and fragility of underwater life and the majesty of wild coastlines.

This awe-inspiring book of photography charts his transformation from marine biologist to full-time conservation advocate, armed with little more than a mask, fins and a camera. In these vivid pages, Peschak photographs sharks in a feeding frenzy, tracks sea turtles the size of bears, and dodges marine poachers, to reveal the splendor of pristine seas as well as the dark side of pollution, overfishing, and climate change.

Filled with magnificent images from Southern Africa, the Galapagos, Seychelles, and more, this illuminating collection offers an impassioned case for revering-and preserving-the world's oceans.