Rabbi Darren Kleinberg, head of school at Kehillah Jewish High School in Palo Alto, takes a deep look at contemporary Jewish identity in his new book “Hybrid Judaism.”

Subtitled “Irving Greenberg, Encounter, and the Changing Nature of American Jewish Identity,” the book focuses on the Brooklyn-based scholar and Modern Orthodox rabbi, his theology and its relevance to 21st-century Jews.

Kleinberg “presents a comprehensive and sophisticated analysis of Rabbi Irving Greenberg’s mature thoughts on a host of subjects crucial to modern Jewish life and religious thought, and does so by situating him against the larger backdrop of American religious history and sociology,” writes David Ellenson, director of the Schusterman Center for Israel Studies at Brandeis University and chancellor-emeritus of Hebrew Union College-Jewish Institute of Religion.

“Hybrid Judaism” by Darren Kleinberg (160 pages, Academic Studies Press)

“Showstoppers!: The Surprising Backstage Stories of Broadway’s Most Remarkable Songs,” by longtime former San Francisco Chronicle columnist and theater critic Gerald Nachman, highlights some of the greatest songs to hit the stage.

“Whether it’s a big toe-tapping showstopper or a small heartrending ballad, these are the so-called take-home tunes, the moments we most cherish, that often sell the entire show to us, push it over the top and ultimately carve out a niche in the Broadway pantheon,” he writes. Among the dozens of songs he includes: “If I Were a Rich Man” (“Fiddler on the Roof”), “All That Jazz” (“Chicago”) and “Springtime for Hitler” (“The Producers”).

Nachman, a native of Oakland, interviewed many iconic musical theater figures and original cast members for the book, his seventh.

“Showstoppers!” by Gerald Nachman (384 pages, Chicago Review Press)