Among a litany of Billboard Hot 100 milestones and achievements, the first artist to reach number one in a band and later solo may surprise you.

In The Beatles' early days, John Lennon would invite Paul McCartney over to write songs. McCartney thinks one of their earliest was about Lennon's parents.

The Monkees' star speaks to PEOPLE about his upcoming tour, his milestone birthday and his unforgettable life in rock 'n' ...