Note: This is an abridged version of The Treasure of the Great Reef (1964). Not the same book as Indian Ocean Adventure which describes Clarke's first visit to the Great Basses Reef in 1958, also with Mike Wilson.

Synopsis: Describes the discovery of a sunken treasure in 1961 and the expedition for its recovery in 1963 in Great Basses Reef, some 10 miles south of Sri Lanka. A great amount of silver coins, cannons and various other artefacts were salvaged. Clarke took little part in all this - not being there in 1961 at all and being incapacitated in 1963 due to severe illness - but observed at close range and even taped some interviews with those who did the job: two American boys, Bobby Kriegel and Mark Smith (13 and 14 years old respectively, to whom the book is dedicated), the photographer Mike Wilson, the famous diver Rodney Jonklaas, and the eminent underwater archeologist Peter Throckmorton.