This is one of the most important documents of Nahuel Moreno. In it is expressed the polemics with another Trotskyist leader, the Belgian Ernest Mandel (1924-1995). Mandel led since the early 1950s the current revisionist of Trotskyism (which identified itself for years as the “United Secretariat"). His written work is well known in the English language, first for his important papers on Marxist economics. In the early 1970s, when he wrote this book, Nahuel Moreno led the PST (Partido Socialista de los Trabajadores) of Argentina, one of the largest Trotskyist parties in the world. In his long journey he devoted much of his militant effort to the building of revolutionary socialist parties in his country and Latin America.