OMAI: The Prince Who Never Was, by Richard Connaughton, Timewell Press, 2005, 270 pp., £16.99 (cloth).

It may not be true that, as the adage has it, every picture tells a story, but if pictures have any tales to tell, then Joshua Reynolds' portrait of Omai has a richer and stranger one than most.

Reynolds (1723-92), the renowned English portrait painter, was the subject of an exhibition at Tate Britain last year. The theme of the London show was "the creation of celebrity," and all the luminaries of the painter's day (cognoscenti, statesmen, actresses and aristocrats) were brilliantly portrayed. But only one picture, a life-size portrait of the young Polynesian Omai, had an entire wall to itself.

Richard Connaughton's admirably thorough and lucid volume relates the story behind the painting, or rather the story of the person in it. Omai (whose real name was probably "Mai") was born on Raiatea, one of the Society Islands, in about 1753. During his youth, the island was attacked by another tribe that murdered Omai's father and drove the family from their native lands. It is likely that Omai was seeking a way to revenge himself upon his enemies when he made friends with the British.