I'm sure many of the models mentioned here are already familiar with students of business and management(like for instance SWOT analysis, team building stages etc). I believe some of the models are from the sociology/psychology field(like the Johari Window). There are even useless models(for me at least) like what you listen to and what you wear can describe what kind of person you are. I do believe that someone can deduce a character of a person(at least to some extent) by the kind of music he listens and the kind of clothes he wears. But this is not always true and it is just so broad and complicated to be pointed out on a single model with two horizontal and two vertical lines. Personally, I believe not all of the 50 models are useful. Some particularly intrigued me like the 80/20 principle. But there's only a short summary for each of this model. Not descriptive enough. But you get an overview. Then maybe you read more about the model you're interested in. This book serves as an introduction. Of course, you will need to carry out all the exercises and apply the models in real-life situations. (Again, some are just hypothetical). If not, you will forget what you've read quite fast.