Exploring the changing relations between humans, marine species and oceans as captured in the biographical writings, art and photography of divers, sea-species biographers and underwater photographers over the last hundred years, Underwater Lives takes a deep dive beneath the surface to reveal what they can tell us about this sublime and increasingly endangered world. With alarm bells ringing and serious questions raised about the sustainability of humans' interaction with the oceans, this book probes such ideas as what can be learnt from an underwater world seen for the first time; how did the advent of cameras contribute to underwater life writings and the spread of oceanic knowledge; how are oceans 'seen' through immersive texts; and how do contemporary underwater life writings engage with the destruction of the Anthropocene? Reading texts and images together, and sometimes against each other, Clare Brant employs life writings to investigate how literary conventions operate underwater, how particular visual conventions shape what we see, how literature partners with other arts to convey ocean life and what underwater life writings have to say about the entangled politics of human engagement with ocean lives. Structured around the lives of both human and non-human, including the ocean itself as a collective life, and covering a broad range of writers and photographers, films and documentaries, the book examines the work of William Beebe, John Williamson, Jacques Cousteau, Robert Gibbings, Eugene Clark, Lotte Hass, Sylvia Earle, Rachel Carson, Heathcote Williams, as well as popular documentaries and films like The Octopus Teacher and Finding Nemo and children's books like Mister Seahorse, Somebody Swallowed Stanley and the Pout-Pout Fish . Joining the growing domain of blue humanities, Underwater Lives brings literary, historical and aesthetic thinking to the oceans as they have been seen through human eyes - and their prosthetics: cameras.