"I started out trying to build a device which would pick up and amplify thought waves. This led to contact with a man on Mars who experimenting in transmitting thoughtwaves-but no the Mars of today, he added, seeing the expression on Jerry's face. 'Lal Vak, the Martian, spoke and still speaks to me from the Mars some millions of years ago, when a human civilization did exist there. We found that personalities could be exchanged between certain Martians and Earthmen who were nearly doubles physically, and whose brain-patterns were similar."
1961