Passage: Guevara arrived in Mexico City on 21 September 1954, and worked in the allergy section of the General Hospital and at the Hospital Infantil de Mexico. In addition he gave lectures on medicine at the Faculty of Medicine in the National Autonomous University of Mexico and worked as a news photographer for Latina News Agency. His first wife Hilda notes in her memoir My Life with Che, that for a while, Guevara considered going to work as a doctor in Africa and that he continued to be deeply troubled by the poverty around him. In one instance, Hilda describes Guevara's obsession with an elderly washerwoman whom he was treating, remarking that he saw her as "representative of the most forgotten and exploited class". Hilda later found a poem that Che had dedicated to the old woman, containing "a promise to fight for a better world, for a better life for all the poor and exploited".During this time he renewed his friendship with Ñico López and the other Cuban exiles whom he had met in Guatemala. In June 1955, López introduced him to Raúl Castro, who subsequently introduced him to his older brother, Fidel Castro, the revolutionary leader who had formed the 26th of July Movement and was now plotting to overthrow the dictatorship of Fulgencio Batista. During a long conversation with Fidel on the night of their first meeting, Guevara concluded that the Cuban's cause was the one for which he had been searching and before daybreak he had signed up as a member of the July 26 Movement. Despite their "contrasting personalities", from this point on Che and Fidel began to foster what dual biographer Simon Reid-Henry deemed a "revolutionary friendship that would change the world", as a result of their coinciding commitment to anti-imperialism.By this point in Guevara's life, he deemed that U.S.-controlled conglomerates installed and supported repressive regimes around the world. In this vein, he considered Batista a "U.S. puppet whose strings needed cutting". Although he planned to be the group's combat medic, Guevara...

Question: Who's tactics did Guevara learn?
guerrilla