Honor Frost has written a travel book with this difference: her journeys have extended below the surface of the sea. Her accounts of these regions can be compared with the writings of early travellers who, unhampered by overspecialization, recorded a variety of observations on completely unknown places. In setting down her direct experience she has thrown new light on the much discussed submect of underwater archaeology. This book contains 22 colour and 28 monochrome photographs by well known divers, also 52 plans and drawings by the author illustrating her arguments. It is addressed to travellers, archaeologists and divers alike, and presents a fascinating theory of submarine excavation in terms allowing anyone interested in marine antiquities to judge whether free-diving must remain a synonym for treasure-hunting or, as a new method of investigation it can be adapted to the interests of science. Marine antiquities are primarily associated with the Mediterranean not only because it was the cradle of western civilization, but because the physical factors of this sea (which Honor Frost describes) uniquely favour the preservation of ancient remains. Further, the technique of free diving was pioneered in Mediterranean waters where it has now developed into a skilled and disciplined profession. In consequence, some Mediterranean divers have acquired a wide comparative knowledge of wreck-formations, ancient harbours and the jetsam that marks the sea-lanes of anitquity.