Journalist and scholar John ("Tito") Gerassi was born in France in July 1931, to Fernando Gerassi, a Turkish-born artist of Sephardic Jewish heritage, and Ukranian born Stepha Awdykowicz. Moving between Barcelona and Paris, the couple belonged to the cosmopolitan circle of artists and intellectuals who congregated in cafes to argue art and politics, and counted Jean-Paul Sartre and Simone de Beauvoir as close friends. When civil war broke out in Spain in 1936, Fernando Gerassi joined the Loyalist forces. He served as a general in the Spanish Army and became the inspiration for the figure of Gomez, the artist and revolutionary in Sartre's trilogy Roads to Freedom. Following the Fascist victory in Spain, the Gerassi family emigrated to the United States in 1940. John Gerassi was raised in New York City and attended Columbia University. He spent a decade in journalism, worked as an editor for Timeand, later, Newsweek before serving as a foreign correspondent for the New York Times. He left journalism to pursue a career in academia and earned his doctorate at the London School of Economics. He was an instructor at the John Kennedy Freedom School in Berlin and at the University of California at Irvine before joining the faculty of Queens College of the City University of New York in 1978. Among his publications are The Great Fear in Latin America (1965); The Boys of Boise (1966); the biography Jean-Paul Sartre: Hated Conscience of His Century (1989); and "The Comintern, the Fronts and the CPUSA," in New Studies in the Politics and Culture of U.S. Communism (1993).

His father's death in 1974 and his own subsequent journey to Barcelona the following year kindled his interest in the Spanish Civil War and the men and woman who volunteered to fight on behalf of the Republic. The Premature Anti-Fascists: Oral History of American and Canadian Volunteers in the Spanish Civil War, Gerassi's tribute to these volunteers, was published in 1986. In the preface to that work, he describes his methodology for selecting and recording the oral histories that became the foundation for his study. In the spring of 1979, Gerassi sent out one-page questionnaires to 300 U.S. and Canadian veterans of the Spanish Civil War:

"From the 210 answers, I selected 50 absolute 'musts' to be personally interviewed. By making another 100 phone calls, I chose another 30. And 50 more were picked along the way, either by Mr. Ray Villis, my principal interviewer, or by myself and Ms. Chantal Ferraro, my main researcher…. Of the 130 interviewed, 65 were fully transcribed; the rest were used for background verification. The resulting 18,000 pages were then edited down by me…. Rather than fill scores of pages with tridots, brackets, and explanatory footnotes, I took the liberty of editing the interviews so that each section could read smoothly as a narrative."

Although the study is a sympathetic and admiring portrait of the veterans as a group, and Gerassi took pains to remain true to the intent and voice of the individual accounts, some of the veterans were displeased with Gerassi's polished edits of their oral histories.