Events that occurred on 4 January.
 On Earth
- 1892 - Arthur Tolkien sends a letter to his mother about his new son.
- 1937 - J.R.R. Tolkien writes Letter 9.
- 1940 - Voice actor David Collings is born.
- 1966 - Author and linguist Arden R. Smith is born.
- 1991 - Actress Olivia Tennet is born.
- 2005 - Biographer and editor Humphrey Carpenter dies.