She popularized the walk-in theory.

George Hunt Williamson (1926 – 1986), aka Michael d'Obrenovic and Brother Philip, was an American flying saucer contactee, channel, and metaphysical author who came to prominence in the 1950s.

UFOs and the New Age movement phenomenon of ‘walk-ins’.

Williamson invented the concept of 'walk-ins,' who he called 'The Wanderers.' Walk-ins are normal humans who are actually (unknown to themselves) reincarnated 'Space Brothers.'