This is a seriously great book.
The subject is our resistance to admitting that we've been wrong about something, how we rationalize our past judgments and choices even in the face of overwhelming evidence that we were wrong.
The phenomenon is universal, we're all prone to it. But why do we do it? Aronson is one of the most influential psychologists of the 20th century, and he introduced the concept of "cognitive dissonance" as a mechanism for explaining this behavior.
Cognitive dissonance refers to the psychological discomfort that we feel when our attitudes and behaviors are inconsistent (dissonant). This discomfort motivates us to either change the behavior or the attitude so that consistency is restored. One of the methods we use to resolve these inconsistencies is rationalization -- telling ourselves stories that make our judgements and actions appear rational to ourselves, and other people.
The book is full of great examples. Tavris and Aronson explain how politicians, pundits, doctors, lawyers, psychotherapists -- all of us -- come to believe that we are right and reasonable, why we maintain this dangerous self-deception even in the face of glaring evidence to the contrary, and why charlatans, scammers and tyrants can sleep at night.
These are important ideas. Every critical thinker should have a working understanding of cognitive dissonance and the rationalization strategies that we're all prone to.