Shysters chase ambulances; critics chase influences. How to characterize this Chandler-Babel stew? Let's try the Hollywood idiom. "The Yiddish Policeman's Union" is Woody Allen meets Cornel Woolrich. No, better, deeper: S.J. Perelman meets Y.L. Peretz meets Harry Turtledove. Martin Amis meets Stanley Elkin who is chatting with Sholom Aleichem about Jorge Luis Borges.