He reached Guatemala during the socialist Arbenz presidency; although he was by now a Marxist, well read in Lenin, he refused to join the Communist Party, though this meant losing the chance of government medical appointment, and he was penniless and n rags. He lived with Hilda Gadea, a Marxist of Indian stock who forwarded his political education, looked after him, and introduced him to Nico Lopez, one of Fidel Castro's lieutenants. In Guatemala he saw the CIA at work as the principal agents of counterrevolution and was confirmed in his view that Revolution could be made only be armed insurrection. When Arbenz fell, Guevara went to Mexico City (September 1954) where he worked in the General Hospital. Hilda Gadea and Nico Lopez joined him, and he met and was charmed by Raul and Fidel Castro, then political emigres, and realized that in Fidel he had found the leader he was seeking.
He joined other Castro followers at the farm where the Cuban revolutionaries were being given a tough commando course of professional training in guerrilla warfare by the Spanish Republican Army captain, Alberto Bayo, author of Ciento cincueto preguntas a un guerrilleo, Havana 1959. Bayo drew not only on his own experience but on the guerrilla teachings of Mao Tse-tung, and 'Che', as he was now called (it means chum or buddy and is Italian origin), became his star pupil and was made a leader of the class. The war games at the farm attracted police attention, all the Cubans and Che were arrested, but released a month later (June 1956). When they invaded Cuba, Che went with them, first as doctor, soon as a Commandante of the revolutionary army of barbutos. He was the most aggressive, clever and successful of the guerrilla officers, and the most earnest in giving his men a Lenist education: he was also a ruthless disciplinarian who unhesitatingly shot defectors, as later he got a reputation for cold-blooded cruelty in the mass execution of recalcitrant supporters of the defeated president Batista. At the triumph of the Revolution Guevara became second only to Fidel Castro in the new government of Cuba, and the man chiefly responsible for pushing Castro towards communism, but a communism which was independent of the orthodox, Moscow-style communism of some of their colleagues.