The book is organized into 25 daily readings, and postulates that by focusing our attention on certain ways of thinking, we can become a more critical thinker, which in turn helps us "observe, monitor, analyze, assess, and reconstruct" our thinking, which can help us live better lives.
After reading this book for the prescribed 25 days, I have to agree that my thinking did improve and my life was made richer by focusing my attention on the daily thinking goals. For example, Day 9 has you thinking through implications; on Day 14 you are to stop thinking like a conformist; and on Day 21 you are to strive to be a citizen of the world.
Once you read through the book, the authors suggest turning this 25 day plan into a 25 week plan whereby you'd focus on each single day's thinking suggestion for an entire week. I will definitely read this book again and again.