The Brownsville of Osheroff's childhood was a working-class neighborhood of strong socialist sentiments, packed with Jewish immigrants like his parents, a carpenter and a sweatshop seamstress. The first language Osheroff spoke was Yiddish. A good student, he graduated from the City College of New York and then headed for the coal-mining country of Pennsylvania and Ohio as a labor union organizer.
In 1936, the Spanish army under Franco rebelled against the government of the republic to ignite a vicious war, an ideological struggle that captured the attention of the world. Hitler sent planes and pilots to Franco's aid, while Mussolini provided troops and other help; Josef Stalin and the Soviet Union assisted the government. Artists and intellectuals from around the world rallied to the republican cause, and so did fighting men and women: 50,000 foreign volunteers made their way to Spain, forming the International Brigades.