Cycling aficionados mourn the passing of Sheldon Brown. I never met the man, but I am very familiar with his website and his cycling tips and techniques. His online gear calculator helped me understand the mystery of my road bikes gears as I went from an 11-21 to a 12-25 to a 12-25 compact crankset. Without him, I would be huffing, puffing, and pushing my bike up the Low-Key Hillclimbs.
Rest in Peace, Sheldon. You’ll be missed.
tow.com 
Wow, it seems like all cyclists have heard of Sheldon Brown! His website is great. RIP, Sheldon.
Amazingly, there is even a Wikipedia entry about him!