What is the strangest secret?

Check out this excerpt from Earl Nightingale's The Strangest Secret. It's only about three minutes. It was recorded in 1956 and it's worth watching. (Not to be confused (or necessarily compared) with The Secret.)

www.thestrangestsecretmovie.com/?cm_mmc=Responsys-_-WK-_-2.20.10-_-TSSCmovie

OK, here's the test. Who was Earl Nightingale (1921-1989)? No fair doing a search before answering.

This reminded me to dust off my album of Nightingale's The New Lead the Field and pull out cassette number 1.