I think though that some books have a large potential benefit (I'm thinking of Mindset right now) because they spend a few 10's of thousands of words changing your mind. Summaries won't have the same effect.
The central idea of the book is revealed in it's description on Amazon : Dweck shows how success in school, work, sports, the arts, and almost every area of human endeavor can be dramatically influenced by how we approach our goals. People with a fixed mindset—those who believe that abilities are fixed—are far less likely to flourish than those with a growth mindset—those who believe that abilities can be developed through hard work, good strategies, and mentorship. Mindset reveals how great parents, teachers, managers, and athletes can put this idea to use to foster outstanding accomplishment.
And then Derek's detailed notes will help me understand the sub-ideas presented by the author as well as any relevant and interesting examples.
The thing is, I'd hate for anyone to miss the experience I had with that book - I really & honestly put myself in the growth-mindset camp, but the book taught me how to see the many, many areas of my life that I had a fixed mindset about.
It's one of the few books that has literally changed my life, so like I said, I'd hate to see people missing out on that (assuming they're in need of it!) by reading a summary.