Often referred to as a champion of the common man, the US painter Thomas Hart Benton was known for his illustrations of Depression-era society. In 1937, Life magazine commissioned Benton to draw a strike by the United Auto Workers Union at General Motors in Michigan. One of the sketches he produced during the trip—Study for Discussion, which was published in Life later that year—shows a labourer and a union recruiter in heated conversation over drinks and a cigar. Thirty years later, Benton created Discussion (1967), a small painting based on the sketch, in which two men of different races discuss the issues faced by workers in the late 1930s. Both works are due to be auctioned at Leslie Hindman in Chicago on 20 May. The painting comes with an estimate of $200,000 to $400,000, and the sketch with an estimate of $6,000 to $8,000.