Martha Holmes explores some of the world's major oceans and the variety of creatures which exist in them. The book is based on a five-part BBC series in which specially-developed technology allows the author and fellow-presenter Mike de Gruy to talk to each other under water. The author describes how it feels to discover animals, plants and fish which live beneath the sea, and each chapter covers a different location, varying from Australia's spectacular barrier reef to the seas of Hawaii and an encounter with humpbacked whales; from the little-known waters of the Galapagos, where sealions cavort with penguins, marine iguanas and even divers, to the waters of the Bahamas and a school of dolphins. Also described are the extraordinary kelp forests of Northern California, home of 750 species of fish and invertebrates, as well as the tiny sea otter.