magnates of Silicon Valley live in a region blessed not only by an extraordinary climate, but also by a beautiful setting protected from development by some of the world's most restrictive land-use controls." The clear implication here, in the context of the argument that Glaeser's been building over several chapters, is that there's somehow something sinister and inequitable about this, and that Bay Area living could be more affordable if only, say, the San Francisco State Fish and Game Refuge were to be opened up for unrestricted development. You have to wonder how seriously he means such arguments to be taken. - "The move to low-density living ended up being far less sensitive to nature than [ Hugh !] Ferriss's vision of a towering metropolis." And here we rise to one of the book's peaks of intellectual dishonesty. But for the provisions of the Clean Air Act and Clean Water Act , America's cities would be no friendlier to nature than India's or China's. Density is a good thing -- a wonderful thing -- but it's only a ground condition for low ecological impact. In order to fulfill its ecological promise, high urban density needs to be accompanied by effective, enforceable and actually enforced environmental regulation. - Every passage that raises the issue of anthropogenic global warming is marked heavily by weasel words: the costs of warming "may well be" enormous, ice caps "appear to be" melting, temperatures fluctuate "for many reasons," and so on. For whatever reason, I get