Holt Side-Hill Combine in the Palouse Hills, Washington, circa 1907

It took hundreds of years to perfect machinery that could combine the three major steps of harvesting grain: reaping, or cutting the crop; threshing to loosen the grain; and separating the grain from the rest of the plant. Early "combines" like this one were unwieldy and could only be used on very large farms. More compact and versatile self-propelled combines became available in the 1930s.