"Decisive" explores how people make decisions and identifies common pitfalls. The authors point out biases like narrow framing, confirmation bias, short-term emotions, and overconfidence, arguing these impede optimal choices. 

The book then provides strategies to counter these biases. These strategies include widening options, reality-testing assumptions, attaining distance from emotions, and preparing for being wrong. The book offers the "WRAP" process as a solution to improving decision-making, offering practical methods and examples to illustrate its effectiveness.

Ultimately, the authors aim to equip readers with tools to make more informed, rational decisions in both personal and professional contexts.