Featuring Vassar faculty member Robert Osborne, bass-baritone, Tammy Hensrud, mezzo-soprano, and Richard Pearson Thomas, piano, the entertaining cabaret revue “Alma Mahler and Her Charmed Circle” will shed light on this remarkable yet overlooked figure through a broad array of art songs, cabaret tunes, satirical songs, and vocal duets interspersed with brief selections from Mahler’s own diaries and correspondence. From the explosively creative milieu of early 20th-century Vienna to her final days in her New York City apartment, a rich portrait of Alma Mahler emerges, placing her at the center of a dazzling array of friends, lovers, and spouses — Kokoschka, Klimt, Korngold, Berg, Zemlinsky, Bernstein, Schoenberg, and so many others.