Augusto C. Sandino (1895–1934) led a peasant rebellion against the armed forces of the United States which occupied Nicaragua between 1926 and 1932. While much has been written about Sandino’s military prowess in this 20th-century guerrilla warfare, less is known about the development of his political thought and intellectual formation. That issue necessarily takes historians to the Mexican Revolution, and specifically to the period between 1923 and 1926 when Sandino was an immigrant worker in the oil fields of the larger Tampico area. Radical labor unionism and anarcho-syndicalism were the principal currents that Sandino encountered, and that helped shape his outlook and subsequent political manifestos. Because Sandino did not directly refer in any detail to this period of his life in subsequent interviews and statements, an examination is made of the cultural and social roots of working-class formations in which he immersed himself. Fortunately, historians have explored the social aspect, labor union activity, economics, and politics of the oil fields in depth (Adleson, Alafita-Mendez, Alcayaga Sasso); Dospital and Hodges were among the first to point to Sandino’s early experience in Mexico including his encounters with the metaphysical schools and mentors who shaped the idealism underpinning his anti-imperialism economic, political, military, and cultural thinking. During a military campaign and at the peak of his fame, Sandino returned to Mexico (1929–1930) expecting that the “revolutionary” government, on the one side, and the Communist Party of Mexico, on the other side, as representative of the international communist movement (Comintern) would lend political, financial, and military support for the war in Nicaragua. Cerdas Cruz told that story well, although without the benefit of primary sources. But Sandino was mistaken and eventually felt betrayed by both sides that laid claim to the revolution. He returned to Nicaragua where he fought successfully until the US Marines’ withdrawal at the end of 1932. Months after signing a peace treaty, Sandino was assassinated (February 1934) in Managua by the leaders of the proxy military constabulary or Guardia Nacional left behind by the United States in Nicaragua. At that time, he was establishing communes in northern Nicaragua according to the teachings of his first intellectual and spiritual mentors.