What is disinformation, and why does it matter? How can we understand and detect different kinds of disinformation? The book's four parts provide the reader with answers and a deeper understanding of various concepts and events: (1) On notions of post-truth and fake news, with examples from the last decade. (2) On the notion of conspiracy theory and the influence of "narratives" that obfuscate the truth of the matter. (3) On the role of algorithms in propaganda and their impact on freedom of expression. (4) On "emergency tools" for detecting disinformation at an individual level, understanding the most hidden mechanisms of the dark side of the speech.From the preface by John Perry (Stanford University):"What to do with this book? Read it from start to finish; it is fascinating. Alternatively, pick out a topic, study the index and learn all about it. I think the book would make a great text for an undergraduate course —- a semester or even a year. But by picking one topic or another, historical or philosophical or a combination, one could put together a great lecture or a seminar. If you find your kids seduced by bullshit from the internet, set them down and explain where it really came from. And for that matter, use the book to help determine whether your own beliefs are information or disinformation."