If you play Guitar in a Pop or Rock band, it was Bert Weedon who taught you. Maybe not directly, but all the Guitarists you loved (Clapton, Townsend, May etc etc) bought that 'Play In A Day' book, read about how the Guitar works, learned E, A and D and then changed the world.
Up until 'Play In A Day', music tuition books had been as dry as dust, but Bert made the learning relevant to the new generation of Guitarists - inspired by Skiffle and eager to form Beat Combos across the land. Romanced by the allure of the Electric Guitar, thousands of people bought the book and enriched their lives with music.
He was a self-effacing guy, never smug and genuinely amazed and righly proud that he had inspired people to learn an instrument. It's only a little bit of a hyperbole that he probably influenced as many people as musicians like Mark Knopfler, Steve Hillage, Sting and the countless others who picked up that book.
Without him, the landscape of music would be very different.