Allen Zwerdling, a founder of Back Stage, the weekly theater newspaper that is widely considered the casting bible for performers, died on Jan. 12 at his home in Rosendale, N.Y. He was 86.

He died of natural causes, said Sherry Eaker, an editor at large and former editor in chief of Back Stage.

Eaker’s father, Ira Eaker, started Back Stage in 1960 with Zwerdling, after the two met working at Show Business, another theater publication. Ira Eaker died in 2002.

The print run was about 10,000 copies a week in 1960, but Back Stage eventually grew to its current circulation of 32,000, according to the paper’s Web site. A Los Angeles-based sister newspaper, Back Stage West, was started in 1994 and now reaches 24,000 readers. Back Stage also has a Web site, Backstage.com, with more than 20,000 paid subscribers.

But circulation numbers do not tell the whole story, as each paper copy may be passed from hand to hand by actors and other theater professionals.