This is a fascinating book. In essence, the author argues that while there are a great deal of the population that cares about inward efficiency (is my life improving regardless of other people's lives), there are also a great deal of populations that mostly care about outward fairness (am I falling behind others? If I am, is it because the game has changed/things are not like before/thus not "fair"). Take the following example:
The Problem: A hardware store has a limited supply of snow shovels during a massive blizzard.
Fairness System: The person refuses to raise prices, believing it is "unfair" to exploit a customer s emergency for profit. They might implement a "first-come, first-served" rule or a limit of one per person. This is inefficient because the shovels may go to people who don't need them most, and the store runs out of stock instantly.
Efficiency System: The person immediately raises the price to the maximum the market will bear. This ensures the shovels go to those who value them most (price as a signal) and provides the store with the capital to incentivize emergency restocking, maximizing the availability of goods in the long run.
The author's main argument is this book is that we ought to account for the fairness population's need in policy making. That essentially we need to have a "fairness" tax built onto the policy in order to ensure the "fairness" thinkers feel everything is "fair". While this might sound abused to the efficiency population, policy makers have to understand that fairness is a rather big congestive style of many people.