This truly is a shame. I'm what one might call an avid amateur photographer, and he was my biggest influence. Like him, my favorite place to photograph is the street, and also like him, I use a rangefinder camera. I don't use a Leica, however; rather, I use a Voigtlander R2 with Leica M glass.
His work is some of the most inspiring street photography, or just photography, ever to have been captured. For those of you who haven't seen his work, you must. When viewing his photographs, it's hard to believe that a man was even present; the subjects are so natural and oblivious to the presence of a photographer.
It's a good thing his work will live on. And so will his concept of the 'decisive moment,' so beautifully demonstrated in all of his images.