It's hard to say what we like best about Michael Dibdin's Aurelio Zen series: his knowing police detective, the thoroughly enjoyable Italian settings, fast-paced plot or wry commentary on contemporary society and poltitics. In this ninth outing, Zen finds a mysterious corpse in a long-abandoned military tunnel in the Dolomites, a perfect opportunity for Dibdin to put his detective on scenic train rides and immerse him in some unsavory WWII-era politics. Zen and Gemma are living quietly (or attempting to) in Lucca after the events of the last book, Blood Rain.  (ITL576, $12.95)