This book explores the ways that the increasing personalisation of the internet affects its users both in the short and long term senses. It also explores many other related issues, including the ethics of mass media, the psychology of advertising, the centralization of internet control, and the internet’s potential both to advance and harm the development of human society. I was very interested to learn that data about internet users is a huge and unbelievably valuable commodity for advertisers and that the gathering, buying and selling of this data is largely behind the scenes, with little accountability and opaque to public scrutiny. This book is scary and challenging, but not sensational or fluffy, as are most books of its ilk. I would have given it 5/5 if Pariser had been a little more scholarly with his handling of citations (there is a detailed “notes” section at the end, but the sources are sorted by chapter and not linked directly to the text, making it time-consuming to verify his claims). I recommend that everyone read this book. It will not be a waste of time.