It's an excellent, excellent book. I guarantee you some utterly fantastic walks from it, many of them exploring some absolute historical gems - none of which you would probably just stumble upon.
I'd echo this. I have recently started to walk everywhere I can in London, instead of getting the bus or the tube, and it has made a big difference to me. You notice a lot more, both positive and negative sights, that really give you a sense of perspective on life.