Orrin Hatch apparently is poised to pen a “tell-all” book — all, that is, about the Mormonism he knows and loves. Hatch — Utah's senior U.S. senator who faces a Republican primary rival next month and, if he prevails then, a Democratic foe in the fall in his bid for a seventh term — plans to take up the challenge of explaining his faith to outsiders in the new volume, An Insider's Guide to Mormon Beliefs.