Frank Conroy, who “headed the Writers’ Workshop at the University of Iowa for 18 years, published just five books, a relatively small number for a writer of his reputation. But one of them was the lucid and evocative 1967 memoir that has been a model for countless young writers – the sort of book that is passed along like a trade secret. But Mr. Conroy was a personal model as well, a sympathetic but exacting teacher who at Iowa helped shape the early careers” of scores of writers.