I was first introduced to Prof. Scott Page by listening to Farnam Street’s podcast called The Knowledge Project. I’ve been increasingly curious about mental models, and this book was my first full book on the topic.
The Model Thinker reduces real-life interactions into mathematical models. If you have not had an undergraduate-level background in mathematics I’d imagine it difficult to follow along, but if you are familiar with math symbols and formula, the book is incredibly interesting and useful.
Page’s claim is that by understanding models of the world, even if imperfect, we can infer actual useful information and normative policies from them. This is, in fact, the entire premise underlying the field of economics. He covers game theory, network effects, path dependence, randomness, signaling, and many other complex attributes of the world that can be simplified to understandable systems.
The single most useful model he gave was his model-of-models, about why no model can be inerrant. He models mathematically why any rule which interacts with the complexity of the real world must have exceptions. This has so profoundly changed my thinking of the world that it earns the book five stars alone. The model is visually presented below:

The realities of the world comprise near-limitless amounts of data (for example, individuals consumption of sugar and their weight). This data can be packaged into information (individuals in a sample who ate more sugar weighed more). Knowledge about the world is in understanding how information relates to other bits of information (eating sugar was the cause of people weighing more). Wisdom is the conditional understanding of how to utilize knowledge to some end (avoid sugar to weigh less). In the model, you see how wisdom is abstracted so far out from the data that it can only speak generally. There is some individual somewhere who will gain weight when they eat less sugar (maybe they over-substitute for fat or other carbs). While abstract things can still be absolute—this model does not invalidate math for example—it makes clear that any wisdom we have about the actual, tangible world must be conditional. It is as close to a formula for humility as you can come by.
This was one of the first, but most impactful of the many models on offer. Consumer behavior, opioid use, social networking, cooperation—all these things can be modeled and put to good use by businessmen, politicians, and also the standard layperson. Consulting the table of contents can give a good overview of what learning is on offer.
The book was also expertly written. It was some of the most concise, clear prose I’ve ever read. It felt like every word and every sentence was useful. Each paragraph fit together to make a point. It’s refreshing to see the work of someone who can be as precise in their English as in their math.
Would not recommend this book if you are unfamiliar with math, but if you know basic notation and want to know how and why the world works in the way that it does, these models are an excellent start. Well worth reading.