I really enjoyed the progression of ideas throughout the book. It captured some of the most important concepts in human history, and went from problem to problem in a smooth manner. It was interesting as a history book, not just as a philosophy book, as it showed how different problems in our society arose, and gave due credit to the schools of thought associated with fixing these problems. It could have earned a five-star rating, but unfortunately the language used was inaccessible at times, and so I'm not sure how well the book serves its purpose of popularising philosophy. I'd think that a teenager with a solid interest would still struggle with motivation to finish the book - some of the content is presented in a rather dry, matter-of-fact style. But the quality of the ideas chosen, and the natural order in which they are presented, win out for me.