Seen at 20 years' remove from the issues that prompted its writing--the Vietnam war, Kent State, waves of ghetto riots, and grief over the murders of John and Robert Kennedy and Martin Luther King Jr.--Leonard Bernstein and Stephen Schwartz's 1971 effort at a Wagnerian Gesamtkunstwerk emerges as much richer and more universal than it originally seemed. Mass, whose influence is clear in subsequent works ranging from Evita to Cats to The Gospel at Colonus), is a theatrically vigorous reenactment and critique of Catholic and Jewish ritual, driven by some of Bernstein's most lyrical and deeply felt music, that speaks powerfully to the conflict between our need for spiritual feeling and our tendency to smother that feeling with pomp and cynicism. With its extravagant scale and stylistic sprawl (its forces include pop and classical soloists, adult and children's choirs, a Broadway-style chorus, a modem dance ensemble, a full orchestra, a rock group, and a marching band). Mass is rarely professionally staged; but it's well served in this skillful, often moving student production directed by Dominic Missimi and conducted by John Paynter. Heading the 200-member company, tenor Eric Van Hoven is excellent in the hugely challenging lead role of the ceremony's despairing Celebrant. Northwestern University, November 15 through 24 (Cahn Auditorium, 600 Emerson, Evanston, 708-491-7282). Fridays and Saturdays, 8 PM; Thursday, November 21, 8 PM; Sunday, November 24, 2 PM; no show Friday, November 22. $10-$15.