A Greek engineer who has written three books in the 10 years he has been writing in English, Panos Karnezis has a command of his second language better than most authors do of their first. Making his name as an elegant stylist with his first book, Little Infamies (2002), a collection of short fables about a nameless Greek Village - and drawing inevitable comparisons to Vladimir Nabokov and Joseph Conrad, two other authors for whom English wasn't their native tongue - Karnezis secured his reputation with The Maze (2004), a novel about the aftermath of the Greco-Turkish war.

In his latest offering, Karnezis has again turned his pen to Greek myth, this time with a fictional treatment of the life of Aristotle Onassis, the late billionaire whose name will forever be linked with the industrial excesses and fantastic wealth of the 20th century.

The most famous shipping magnate of the previous century, equally renowned for his bad temper, womanising and fabulous wealth, Onassis' tale has been told many times before. Gossip columns, essays, biographies, movies and even an award-winning Broadway play have all explored his life.

To their number Karnezis has added The Birthday Party, a re-imagination of Onassis' life that takes a number of liberties with the truth and makes full use of the novelistic freedom to analyse, caricature and dramatise people and events.

The story centres on Marco Timoleon, a ruthless Greek shipping tycoon and self-made man who owes his enormous fortune to his abundant self-confidence and willingness to flout the rules. The parallels between Timoleon and Onassis are laid plain throughout the novel, but there's also a considerable amount of invention in the story, which tracks the course of a day in the summer of 1975. Recounted by a biographer who has become entangled in the story himself, the book opens as the ailing Timoleon prepares to throw one of his legendary parties to mark the occasion of his daughter's birthday. Taking place on his private island in the Ionian Sea, it's soon revealed that this is not a convivial family gathering, but rather an elaborate ruse concocted by Timoleon to convince his daughter to deal with a secret pregnancy of which he doesn't approve.

As guests from around the world begin to arrive, a fully equipped operating theatre in the house is prepared and Timoleon's personal physician, Dr Patrikios, stands by to perform the necessary procedure.

Deftly interwoven into this plot is the back story of Timoleon's life, beginning with his boyhood in Gizmo, where he deals with an absent father by seeking refuge in the world of commerce, a journey that sees him hone his skills for manipulation and build his fortune in Buenos Aries, London, Paris and New York.

Karnezis renders these two stories with impressive imagination and insight. Written in an austere and compelling style, The Birthday Party is simultaneously a gripping tale in its own right and also a challenging look at the nature of celebrity and truth.

At its core, though, Karnezis' novel is an exploration of the lives of the super rich and the public personalities - drawn from fact and theatre in equal measure and perpetuated by others as much as themselves - that surround them. To this end, there's no better choice of protagonist for Karnezis than one modelled on Aristotle Onassis, the prototypical industrial tycoon and a man so decadent, it was once reported that he had the ivory bar stools on his luxury yacht upholstered in whale's scrotum.

In confronting this mish-mash of myth and truth Karnezis has written a beautifully measured book. A mixture of levity and drama, his latest novel lends shape and significance to the story of the super-wealthy in a way that biography can't: by entering the mind of a man and an archetype whose motivations have long been obscured by the trappings of fame, gossip and personal fortune.