Let me start by relating how I first came to be involved with 9/11. I had heard there was some doubt about how the towers and building 7 (WTC 7) came down but, like most people, did not pay this much attention. Then I heard reports that the buildings had come down too fast, close to free fall, and it struck me that this was something for which I did not have to rely on others, as I could check it myself. I got hold of some software, FrameShots, free on the internet, and examined the videos, frame by frame. There is better software available now, but I was able to confirm that the initial movement of all three buildings was suspiciously fast. The calculated downward acceleration was remarkably uniform and too close to free fall during the entire period while the roof was visible. I realized that it didn’t matter that the final moments of the collapse could not be studied this way, being obscured by dust, as the physical action at the beginning was enough to reveal the character of the collapse.