Donna Leon’s The Jewels of Paradise (Heinemann, £17.99)has a promising premise. A young musicologist, Caterina Pelligroni, returns to Venice to trace a legacy left by the 17th-century composer Agostino Steffani, a slippery customer who mixed libretti with realpolitik in the courts of Europe. The bequest turns out to consist mainly of nasty secrets, which seem strangely important to the attractive yet shady lawyer who has hired Caterina.

But despite having all the ingredients of a zippy historical mystery in an intriguing new genre, Jewels doesn’t quite deliver the goods. Caterina spends too much time in libraries, furtively eating energy bars, for the climax to have much more tension than an essay crisis.

Leon seamlessly interweaves the Italian cultural heritage into her story, and hasn’t lost her feeling for everyday life. Her observations of venal Italians and their delicious lunches are bright spots in a plot which often feels like a short story padded out with paeans to the glories of academia. A number of developments simply fizzle out, while Caterina — prone to self-congratulation on her ‘inability to be bland’ — is less like Leon’s previous hero, Inspector Brunetti, than his wife, the less likeable Paola.

Even Paola might think that one of Caterina’s sources, a historian who prefers ‘to read manuscripts not souls’, is a bit limp, but it sums up the problem here: too many manuscripts, not enough pizzazz.