By the early to mid-1970s Brezhnev had established a strong enough power base to effectively become leader. According to historian Ilya Zemtsov, the author of "Chernenko: The Last Bolshevik: The Soviet Union on the Eve of Perestroika", Kosygin "began to lose power" with the 24th Party Congress in 1971 which for the first time publicized the formula 'the Politburo led by Brezhnev'". Along with weakening Kosygin's position, Brezhnev moved to strengthen the Party's hold on the Government apparatus, weakening Kosygin's position further. Historian Robert Wesson, the author of "Lenin's Legacy: The Story of the CPSU", notes that Kosygin's economic report to the 25th Party Congress "pointed even more clearly to the end of struggle" between Brezhnev and Kosygin. Kosygin was further pushed aside when Brezhnev published his memoirs, which stated that Brezhnev, not Kosygin, was in charge of all major economic decisions. To make matters worse for Kosygin, Brezhnev blocked any future talks on economic reform within the party and government apparatus, and information regarding the reform of 1965 was suppressed.