Rabbi Telushkin (An Eye for an Eye, 1991), rooted in the tradition of reverence for past learning, has gathered lots of hoary jokes and aged wisecracks, together with a few more recent japes, that make Jews laugh. To coreligionists, they'll seem like old friends; to others, the gags and their elucidation may be more in the nature of revelation. Another book of ethnic gags? Hold the cry of ``gevalt!'' because Telushkin has an unstated agenda. True to his calling, he uses the funny stuff to instruct. In this collection (in which some bits are, naturally, funnier than others), everything stands for something else--but all of it carries explanations. The exegesis of the jokes becomes a little primer on a religion and a way of life mystifying to strangers and sometimes just as puzzling to nominal adherents. It's a truism that Heisenberg's Uncertainty Principle applies to humor--observing and analyzing it alters it. That effect can be seen here as Telushkin trots out Jackie Mason and Sigmund Freud, as well as Leo Rosten and a host of Unknown Comics for a higher purpose. The tales of the wise rabbis, the fabled fools of Chelm, the anti-Semites, the schnorrers, and the big shots all serve to illustrate his lessons. Was the shtetl a forerunner of Catskills on Broadway? Why are comedians so often Jewish? Why are Jews so often comedians? Why ask questions? Just listen to the rabbi and his jokes. Fine, funny fare for Jew and non-Jew alike.