John C. Bogle ("Jack") is probably the most influential investor of all time. I was lucky to interview him at the CFA Institute Annual conference, and even luckier to get his autograph on a copy of an article (Michael Porter's What is Strategy?) with the diagram below inside.
And here is the interview:
This interview was first published on the CFA Institute website under the title Looking Forward after 40+ Years at the Vanguard.