A Beam of Light — Andrea Camilleri

When Inspector Montalbano falls under the charms of beautiful gallery owner Marian, his longtime relationship with Livia comes under threat. Meanwhile, he is also troubled by a strange dream as three crimes demand his attention: the assault and robbery of a wealthy merchant's young wife, shady art deals, and a search for arms traffickers that leads him deep into the countryside, where the investigation takes a tragic turn.