The Jewels of Paradise, By Donna Leon. Heinemann, £17.99

The opera-house setting of Donna Leon's first novel, Death at La Fenice, was no accident. She has always been a serious student of music and this new work, a departure from her crime-fiction, features a splendid mystery surrounding the inheritance of an obscure baroque composer. His papers are locked in two trunks fought over by greedy rival descendants who decide to employ a scholar to investigate the contents.

Their hope is to find valuable manuscripts or precious objects, but young Caterina Pellegrini, returning to her native Venice, delights in musical research for its own sake. When a suave emissary summons her to an interview, she cannot resist the lure of the past.

The book is based on the life of Agostino Steffano, an almost forgotten composer, extensively researched by Leon and the soprano Cecilia Bartoli, who has recently recorded his arias. Steffano, born in 1654 in Venice, moved to Austria where he became Kapellmeister in Hanover and befriended Handel. But what was his strange personal life and what valuables might he have left?

For Caterina, the possibility of discovering unknown scores is the most entrancing part of her project, but others are motivated by different concepts of treasure. Caterina finds herself in danger in her own city, followed through its foggy alleyways. However, she can fall back on her family, especially on the help of a sister who has become a nun but finds that the dogmatic rulings of the Vatican are alienating her from her religion. Leon shows us the balancing-act required to mediate between the world and the spiritual life as a feature of the present as well as of the 18th century.

From Steffano's patchy biography, Leon has forged a fascinating historical mystery. Full of authentic detail and wittily recounted (Caterina's sojourn at a British university with its badly dressed scholars is a joy), Leon's 22nd novel has a freshness which indicates her delight in her subject, and perhaps celebrates a release from the treadmill of the Brunetti stories.