The reading public seems to have a huge appetite now for religious conspiracy thrillers, and while it's a genre that overall leaves me cold, The Secret Supper by Javier Sierra is at least a convincing examination of the hidden messages in Leonardo Da Vinci's The Last Supper.

Set in the late 1400s, in the time of Leonardo himself, the book was translated from the original Spanish and is read here by Simon Jones, whose theatrical, plummy tones add some drama to a story that often gets bogged down in bland characterizations and digressions from the central plot.

Our hero, Father Agostino Leyre, is a peculiar but interesting feature of the book, though he's never quite given enough personality to spark much curiosity. Sierra has created a protagonist who is kind, intelligent, but difficult to root for. His quest must succeed for the mystery of the book to be solved, but his quest is to suppress artistic expression and impose conformity to religious dogma. The Father is an Inquisitor, a monk charged with suppressing heresy in the time of Pope Alexander VI , having come to the monastery of Santa Maria delle Grazie in Milan to investigate Leonardo and his painting for being part of a heretical movement.

It's difficult to listen to The Secret Supper or even hear its premise, without thinking of that other popular book abut Leonardo. The Da Vinci Code, by Dan Brown, preceded Sierra's, but they are not very similar in tone or style. Sierra's is less breathlessly driven by intrigue, more academic. It's meticulous in its examination of one of Leonardo's masterpieces and the artist himself is a character in the book - an imposing figure physically, spoken of in awe-struck admiration, but never really popping off the page as a developed character.

The loose plotting means that other attempts to inject mystery tend to fall flat. There's a murder at the beginning, of a character who drops in just for that purpose and who isn't mentioned again until long after I'd forgotten about it. The mysterious figure who kick-starts the plot, the Soothsayer, disappears from the action for long periods of time and the code he provides that Leyre must decipher is just one of a confusing array of clues that lead to the ultimate, rather anti-climactic resolution.

As a non-Catholic, I felt I needed to read a history of Catholicism and heretical movements in the Middle Ages to fully appreciate the book. But more importantly, without a copy of the painting in question in front of me or some of the other visual elements described in the book, the revelations were not as revelatory as they otherwise might have been. The cover of the audiobook does have a detail from the painting, but omits many of the relevant portions. I don't know if the book edition is illustrated, but not including an enhanced CD with supplementary illustrations seems like a missed opportunity. (Though, since I listen to audiobooks while driving, I suppose it's just as well I wasn't trying to pore over illustrations at the same time).

The Secret Supper is available unabridged on eight compact discs, as an ebook or digital audio file, and in an abridged version on compact disc. For more information, visit Simon and Schuster's audiobook website, SimonSays, where you can also hear a clip and listen to a podcast about the book.