* Family: His parents were Alfred Lennon and Julia Stanley. John had a younger sister, Julia Baird.
* Early life: Lennon's father abandoned the family when he was five, and his mother later gave him up to be raised by his aunt and uncle, Mimi and George Smith.
* Music career: Lennon began his music career with the Quarrymen, a skiffle group that he formed at the age of 15. In 1960, the Quarrymen evolved into the Beatles, one of the most successful bands in history.
* Writing partnership with Paul McCartney: Lennon and McCartney wrote over 200 songs together, many of which are considered to be classic rock and roll anthems.
* Solo career: Lennon launched his solo career in 1969 after the Beatles disbanded. He released a number of successful albums, including "John Lennon/Plastic Ono Band" (1970), "Imagine" (1971), and "Double Fantasy" (1980).
* Activism: Lennon was a vocal opponent of the Vietnam War, and he and Yoko Ono often took part in anti-war demonstrations. He was also a supporter of animal rights and vegetarianism.
* Assassination: John Lennon was shot and killed outside his apartment building in New York City on December 8, 1980. He was 40 years old.
* Legacy: Lennon is considered to be one of the most influential figures in 20th-century music and culture. His music and message of peace and love continue to inspire people around the world.