In each of these schools, the process of strategy formulation itself is regarded as something of a "black box" none of them are able to clearly describe how an individual or group is able to leap from the collection and analysis of information, to the conceptualization of alternative courses of action (although they do concede that the cognitive school comes closest). Overall, the authors appear to prefer the 'learning school' (they are teachers, after all), because of the emphasis that it places on an organization incorporating input from its environment, and adapting over time.
In the final analysis, just as none of the blind men's descriptions of the elephant was completely adequate, yet each contained elements of truth, none of these 10 approaches is complete in and of itself, either. Each offers some useful concepts, and some strong points to aid understanding, but has its disadvantages as well (again, see the chart).
As well as providing a useful illumination of the origins and characteristics of the different schools of thought, Strategy Safari also makes for a very enjoyable and entertaining read. Mintzberg et.al. have done an excellent good job of taking a difficult and potentially deadly boring subject and rendering it interesting. The book is highly recommended for anyone embarking upon, or engaging in, a strategic planning process.