Clarence Shepherd Day, Jr. (November 18, 1874 - December 28, 1935) was an American author. He was born in New York City. He graduated from Yale University in 1896. The following year, he joined the New York Stock Exchange, and became a partner in his father's Wall Street brokerage firm. Day enlisted in the Navy in 1898, but developed crippling arthritis and spent the remainder of his life as a semi-invalid.
Day's most famous work is the autobiographical Life with Father (1935), which detailed humorous episodes in his family's life, centering on his domineering father, during the 1890s in New York City. Scenes from the book, along with its 1932 prequel, God and my Father, and its posthumous 1937 sequel, Life with Mother, were the basis for a 1939 play by Howard Lindsay and Russell Crouse, which became one of Broadway's longest-running, non-musical hits. In 1947 - the year the play ended on Broadway - William Powell and Irene Dunne portrayed Day's parents in the film of the same name. Life with Father co-starred a young Elizabeth Taylor and an even younger Martin Milner (later one of the two police-officer stars of the 1968 TV series Adam-12), and received Oscar nominations for cinematography, art direction, musical score and best actor (Powell). Life with Father also became a popular 1953-1955 television sitcom.
Day was a vocal proponent of giving women the right to vote, and contributed satirical cartoons for U.S. suffrage publications in the 1910s. According to James Moske, an archivist with the New York Public Library who arranged and catalogued the library's Clarence Day Papers, a survey of Day’s early short stories and magazine columns reveals "he was fascinated by the changing roles of men and women in American society as Victorian conceptions of marriage, family, and domestic order unraveled in the first decades of the twentieth century."
A long-time contributor to The New Yorker magazine, Day sometimes wrote using the pseudonym B. H. Arkwright.
Day's "In the Green Mountain Country" recounted the 1933 death and funeral of U.S. president Calvin Coolidge. His essay collection, The Crow's Nest, received a favorable review in The Nation magazine by the prominent U.S. academician Carl Van Doren; a revised edition with new essays, poems and drawings was published after Day's death under the title After All.
Day achieved lasting fame in literary circles for his comment, "The world of books is the most remarkable creation of man. Nothing else that he builds ever lasts. Monuments fall, nations perish, civilizations grow old and die out; and, after an era of darkness, new races build others. But in the world of books are volumes that have seen this happen again and again, and yet live on, still young, still as fresh as the day they were written, still telling men's hearts of the hearts of men centuries dead."
Day died in New York City shortly after finishing "Life with Father," without ever getting to experience its success on Broadway or in Hollywood.
His uncle, Benjamin Day, was the inventor of the Benday printing process.