Walk Appeal promises to be a major new tool for understanding and building walkable places, and it explains several things that were heretofore either contradictory or mysterious. It begins with the assertion that the quarter-mile radius (or 5-minute walk,) which has been held up for a century as the distance Americans will walk before driving, is actually a myth.
Both images below are at the same scale, and the yellow dashed line is a quarter-mile radius. On the left is a power center. As we all know, if you're at Best Buy and need to pick something up at Old Navy, there's no way you're walking from one store to another. Instead, you get in your car and drive as close as possible to the Old Navy front door. You'll even wait for a parking space to open up instead of driving to an open space just a few spaces away… not because you're lazy, but because it's such a terrible walking experience.
The image on the right is Rome. The circles are centered on the Piazza del Popolo (North is to the left) and the Green radius goes through the Vittorio Emanuele on the right. People regularly walk that far and then keep on walking without ever thinking of driving.
It is not evident, though many people, from the early Greeks on, implicitly act as if it were true, that all things, whatsoever they may be, can be put into words—you could talk about anything: the gods, truth, beauty, and justice. But if you consider what happens in a music concert, then it is obvious that what is transmitted to the audience cannot be put into words—if it could, then the composer and musicians would probably have used words. All the music critics to the contrary, what music communicates cannot (apparently) be put into words. Similarly, but to a lesser extent, for painting. Poetry is a curious field where words are used but the true content of the poem is not in the words!