James M. McPherson, "Lincoln, Abraham," American National Biography Online, February 2000, http://www.anb.org/articles/04/04-00631.html.
During the 1850s he became one of the leading lawyers in the state. His annual income reached $5,000. The burst of railroad construction during the decade generated a large caseload. Lincoln at various times represented railroads…. Yet it would be misleading to describe Lincoln as a "corporation lawyer" in the modern sense of that term, since he opposed corporations with equal frequency…. Lincoln continued to ride the circuit each spring and fall; the great majority of cases handled by Lincoln and Herndon (some 200 each year) concerned local matters of debt, ejectment, slander and libel, trespass, foreclosure, divorce….