As a scholar, Mencken is known for The American Language, a multi-volume study of how the English language is spoken in the United States. As an admirer of the German philosopher Friedrich Nietzsche, he was a detractor of religion, populism and representative democracy, which he believed to be a system in which inferior men dominated their superiors. Mencken was a supporter of scientific progress, skeptical of economic theories and critical of osteopathic and chiropractic medicine.
Mencken opposed American entry into World War I and World War II. His diary indicates that he was a racist and anti-semite, and privately used coarse language and slurs to describe various ethnic and racial groups (though he believed it was in poor taste to use such slurs publicly). Mencken also at times seemed to show a genuine enthusiasm for militarism, though never in its American form. "War is a good thing," he once wrote, "because it is honest, it admits the central fact of human nature… A nation too long at peace becomes a sort of gigantic old maid."
Mencken's longtime home in the Union Square neighborhood of West Baltimore was turned into a city museum, the H. L. Mencken House. His papers were distributed among various city and university libraries, with the largest collection held in the Mencken Room at the central branch of Baltimore's Enoch Pratt Free Library.
Mencken was born in Baltimore, Maryland, on September 12, 1880. He was the son of Anna Margaret (Abhau) and August Mencken, Sr., a cigar factory owner. He was of German ancestry and spoke German in his childhood. When Henry was three, his family moved into a new home at 1524 Hollins Street facing Union Square park in the Union Square neighborhood of old West Baltimore. Apart from five years of married life, Mencken was to live in that house for the rest of his life.
In his best-selling memoir Happy Days, he described his childhood in Baltimore as "placid, secure, uneventful and happy."