Two entertainment moguls are braving the e-book publishing business with the launch of Brightline, a venture created in partnership with Brooklyn-based publishing start-up Atavist. Brightline will publish e-books and eventually physical books. With powerful founders—Scott Rudin, a film and theater producer, and Barry Diller, chairman of InterActiveCorp—the company could bring some competition to the dynamic digital publishing industry, in which Amazon controls 65 percent of e-book sales.