The debut of Nabb's Marshal Guarnaccia, a Sicilian living in Florence. Like Columbo, Guarnaccia is not quite at home -- and deceptively clever. The investigation of the death of A. Langley-Smythe, a seemingly respectable Englishman, unspools on Christmas Eve on the streets of Florence. Scotland Yard dispatches assistance but it is the quietly effective Guarnaccia who solves the case.  (ITL639, $14.00)