David Blum, the author of Tick, Tick, Tick, about the history of CBS's 60 Minutes, said Sunday that Mike Wallace did not voluntarily agree to leave the magazine show. Appearing on CNN's Reliable Sources, Blum was asked by Howard Kurtz, the show's host, whether Wallace got "a shove from CBS." Blum replied, "They've been trying for the past several years to get him to cut back, and he would always agree, and then he would always produce far more pieces than he was contracted to do. They were very anxious to open up not only that slot, but also that considerable amount of money that he was earning to hire younger correspondents, more correspondents to fill out the show." Blum said that even after announcing at age 86 that he was cutting back, Wallace continued to rifle through other correspondents faxes "to see what everybody else was working on so that he could get there first. He was always the most aggressive correspondent at 60 Minutes from the very beginning, and he really never stopped." The problem, Blum commented, was that Wallace was no longer attracting viewers. "And to spend that many millions of dollars to keep him on staff every year just wasn't cost-effective spending for CBS when they could better devote it to Katie Couric's salary, for example."