Whether their tastes were for opera, jazz, rock `n' roll, classical or country & western - maestros of mystery such as Agatha Christie, Cornell Woolrich, George Baxt and Lillian de la Torre often found homicidal inspiration in music. Agatha Christie's "Swan Song" stars Mme. Paula Nazorkoff, the quintesential diva, and Edward D. Hock's "The spy Who Went to the Opera" takes undercover agent Jeffrey Rand back-stage. Lynne Barrett goes on the road with a colourful Elvis impersonator, while in "The Family Rose" Charlotte Hinger spotlights a fading country-western singer. On a different note, John Lutz's private eye Nudger trails a blues singer through the jazz clubs of New Orleans and Doug Allyn's gumshoe tracks down a record company's unpaid royalties - with fatal results.