Disappointing book full of generalities, approximations, incantations or ready made redundancies and flashbacks, of unsubstantiated personal opinions verging on account of payment. Jarvis pushes the doors open and the pub is cheap. This lack of distance. Boring to read, pretentious and ultimately very little concrete. We left hungry because nothing is really detailed about the technical google. The summary you will learn just as much. Too bad because the subject has a real consistency.