Richard Snyder, a visionary and imperious executive at Simon & Schuster who in bold-faced style presided over the publisher’s exponential rise during the second half of the 20th century and helped define an era of consolidation and growing corporate power, has died. He was 90. Snyder died Tuesday at his home in Los Angeles, according to his son Matthew Snyder, who said he had been in failing health. He joined Simon & Schuster as a sales assistant in the early 1960s, when publishing houses were mostly privately owned, some still run by their founders. By the time he was forced out by Viacom in 1994, Simon & Schuster and such rivals as Random House and HarperCollins were under corporate ownership and had bought out numerous former competitors. He was President of Simon & Schuster Inc. starting in 1975, and CEO from 1978 to 1994, He was fired for not being a “team player” and his career never recovered. Mr. Snyder’s four marriages, to Joni Evans, Ruth Freund, Laura Yorke and Terresa Liu, ended in divorce. In addition to his son Matthew, from his marriage to Ms. Freund, he is survived by a daughter from that marriage, Jackie; two other sons, Richard Elliott Snyder Jr. and Coleman Yorke, from his marriage to Ms. Yorke; and two grandchildren.