When John Steinbeck accepted his Nobel Prize for Literature in 1962, he described the writer’s obligation as “dredging up to the light our dark and dangerous dreams for the purpose of improvement.” For some critics, that purpose has obscured Steinbeck’s literary value. He has been characterized variously as an advocate of socialist-style solutions to the depredations of capitalism, a champion of individualism, a dabbler in sociobiology, and a naturalist…