“As a technology, the book is like a hammer. That is to say, it is perfect: a tool ideally suited to its task. Hammers can be tweaked and varied but will never go obsolete. Even when builders pound nails by the thousand with pneumatic nail guns, every household needs a hammer. Likewise, the bicycle is alive and well. It was invented in a world without automobiles, and for speed and range it was quickly surpassed by motorcycles and all kinds of powered scooters. But there is nothing quaint about bicycles. They outsell cars.”