H. L. Mencken (1880-1956), American journalist, critic, and essayist, whose perceptive and often controversial analyses of American life and letters made him one of the most influential critics of the 1920s and 1930s. Born in Baltimore, Maryland, Henry Louis Mencken began his career as a journalist in 1899 with the Baltimore Morning Herald; in 1906 he switched to the Baltimore Sun, where he remained in various editorial capacities for most of his life. With American drama critic George Jean Nathan he coedited Smart Set, a satirical monthly magazine, from 1914 to 1923. Again with Nathan, in 1924, Mencken founded the American Mercury, the literary heir to their previous joint endeavor; Mencken remained as its editor until 1933. The shortcomings of democracy and middle-class American culture were the targets of Mencken's wit and criticism. (He called the American public the “booboisie.”) A six-volume collection of his essays and reviews, entitled Prejudices, was published between 1919 and 1927. Mencken's most important piece of scholarship was The American Language (1919; revised editions, 1921, 1923, 1936, 1963; supplements, 1945 and 1948), which traced the development and established the importance of American English. Happy Days (1940), Newspaper Days (1941), and Heathen Days (1943) are Mencken's autobiographies.

Beginning in 1971, Mencken's letters, diaries, papers, and unpublished manuscripts were periodically released under the terms of his will. Their contents revealed the complexities of his personality and raised allegations of anti-Semitism, racism, and misogyny. The books published from Mencken's posthumously released writings include Mencken and Sara: A Life in Letters (1987), correspondence between Mencken and his wife; The Diary of H. L. Mencken (1989), from the journal Mencken kept from 1930 to 1948; and My Life as Author and Editor (1993), an autobiographical volume.