An eye-opening account of time served in the great battles of our century-- for workers' rights, against Fascism, Communism, and racism--Jumping the Line is the life story of an American original. William Herrick chronicles his adventures and misadventures on the front lines of the Spanish Civil War, in (and very much out of) the Communist Party, driving a tractor on a communal farm in Michigan, jumping the line as a hobo, organizing African American sharecroppers in Georgia, at work with Orson Welles, and immersed in his own writing.      Herrick chronicles a life of great conviction and great disillusion. He went to Spain in 1936 to fight against the Fascists and there witnessed the horrifying acts that Fascists and Communists alike committed, before he was felled by a near-fatal wound. Here he tells about the life that led him, a working-class Jewish kid from New York, into the idealism and then the murky politics of this internecine conflict. From the bloody fight in Spain he takes us to the battlefields of the Communist movement in the U.S., where he found himself parading up and down the garment district of Manhattan, denouncing his former comrades.      When Paul Berman interviewed Herrick in the Village Voice in 1986, for the fiftieth anniversary of the Spanish Civil War, Herrick's remarks so incensed other veterans of the Abraham Lincoln battalion that they picketed the paper. What William Herrick has to say doesn't always go down easily. But for those who like the truth, with a dash of wit and a healthy dose of history, it can be exhilarating.