"The leader must show spirit and have visible faith in the future, despite of the dire state of the organization." (P.181)

Management and leadership is not an exact science (although it is often presented). Complex situations are not uncommon, the rule rather in everyday life. And since models come into play. This should help to understand situations and make decisions and choices. In the book, 56 models (Key Management Models) are presented. Each is examined after 3 criteria (The Big Idea, When to use it, The Final Analysis). Undoubtedly, the knowledge of the models will help to structure information and bring order to chaos, but - as with all models, the bought with reduction.
If desired, I would have an assignment the models according to major categories (eg Financials, Organization etc.) They are arranged alphabetically. In addition to many well-known concepts (SWOT, BCG, 7S, Maslow, marketing mix), there are also a number of less popular models. In this respect, the book is worthwhile in any case, and it can be all managers (who take their job seriously) recommend and also students.