It seems churlish, now that the Library of America has brought out the complete Mencken Prejudices in two handsome volumes, to raise a complaint about the apparatus, especially since the notes are so helpful in identifying figures who have dropped into obscurity. But I believe I have found a mistake.

The passage “They chortled and read on when Aldrich, Boss Cox, Gas Addicks, John D. Rockefeller and the other bugaboos of the time were belabored every month ...” in “The American Magazine” is linked to a note that identifies “Boss Cox” as James Middleton Cox, the newspaper publisher from Dayton, Ohio, and 1920 Democratic presidential candidate.

Surely this gloss, which numbers figures such as Nelson Aldrich and John Edward Addicks in a context of political corruption, should instead identify a different Ohioan, George Cox of Cincinnati, familiarly known as “Boss Cox.” He was a conventional big-city political boss, flourishing in an atmosphere of graft and patronage from the mid-1880s until his fall from power in 1911. He was attacked by Lincoln Steffens and other muckrakers of the age.

James Middleton Cox, by contrast, was a reformer.