John Eaton, formerly a prof at Indiana University, recently joined the music faculty of the University of Chicago, taking over the teaching chores that used to be handled by his pal Ralph Shapey. Very much an iconoclast and an original thinker–and the recipient of a MacArthur Foundation fellowship–Eaton is arguably the most imaginative American composer writing for the voice today; his 1978 opera Danton and Robespierre, for example, offers a remarkably vivid, thoroughly modern kaleidoscope on the exhilarations and cruel politics of Franci’s Reign of Terror. Eaton will introduce his latest vocal work at the Contemporary Chamber Players’ Paul Fromm Concert, an annual event given by the players in honor of their late patron. Titled Notes on Moonlight, Eaton’s song cycle expresses in music five poets’ different perceptions of the moon’s spell: mysterious and malevolent (Garcia Lorca), empathetic and maternal (Wallace Stevens), mocking and ironic (Leopoldo Lugones), luxuriant (Baudelaire), pure and profound (Yeats). Soprano Rebecca Berg and mezzo-soprano Nelda Nelson are the moon worshipers. The program also includes Schoenberg’s Three Little Pieces for chamber orchestra, Shulamit Ran’s Verticals for piano (with soloist Abraham Stokman), and Christopher Rouse’s Ku-Ka-Ilimoku, a ferocious percussionfest meant to evoke the personality of the Hawaiian god of war. Shapey, whose snub by the Pulitzer Prize board last week caused a minor scandal, will conduct. Tonight, 8 PM, Mandel Hall, University of Chicago, 1131 E. 57th; 702-8068.