In her ambitious new book, The Walkable City (Véhicule Press, 2008), Mary Soderstrom writes: "The walkable city, the oldest kind of city is going to be the key to whatever success we have in meeting the challenges of the future."
After all, until the early nineteenth-century people moved only as fast and as far as their feet could carry them. Urban centres had to mirror this fact, whether they developed organically, like in Europe, or according to self-conscious plans, like in North America. Residents lived close to their work until the rise of the suburbs, expressways, and shopping malls separated residential from commercial districts. In many cities since that time, there's been a distinct lack of streets that invite walking. Soderstrom sets off to examine the planning policies and circumstances that have made cities the way they are; to find out what makes neighbourhoods walkable; and to assess how cities can achieve a more walkable, more livable, and greener future.
http://torontoist.com/2008/10/crossing_paths_in_the_walkable_city.php