This is a scary book, and an important book. Greenwald is a clear writer. He manages to get across the information Snowden leaked from the NSA in a readable and even fairly pleasant manner. That’s very important, but not fun reading. The more exciting part of the book deals with Greenwald’s experience documenting Snowden, and his views on the importance of whistleblowing and truly free press. Understanding the scope of the surveillance state that the NSA has built is an important part of understanding the modern world. It makes me angry, but I’m glad I have some idea of what’s going on. It might make you paranoid, but in a reasonable way. Paranoia and concern is the right response.