This book has information for military theorists, biologists exploring gene regulation, antitrust policy-makers, and Miss Manners. It is a wonderfully clear explanation of how almost any two entities, interacting over time, develop a mutualism more profitable than greed.
The experimental support for these claims comes from a series of contests. Dozens of authors provided computer programs to play in the Iterated Prisoner's Dilemma - a simple model, but one that describes a surprising number of real-world phenomena. Most importantly, it's a testable model. It almost puts a common aspect of social interaction into a test tube. What came out of that test tube was startling in its clarity and simplicity.
The book is very readable. Axelrod segregates the mathematical and non-mathematical discussions with some care. Math-free readers see the whole set of experiments and conclusions, clearly explained, and need to skip only a few paragraphs during the main discussion. The last few chapters reward math-positive readers with additional precision and rigor. Even then, the math is accessible to someone with good high-school algebra skills.
Axelrod's discussion truly timeless, except for references to the Cold War as current events. I can accept that. Even though that un-war is mostly over, it's a critical part of modern history and it still informs current policy. Any insight into that madness helps, and Axelrod is very helpful.
This book stands above any one category. It's one of very few that I recommend to the bookshelves of every educated person.