This text provides an introduction to the book as a whole, focusing on topics that were much discussed during its preparation and writing. It gives a critical overview of some main events, public and academic discussions, related to post-truth, and of the volume’s individual contributions. It argues that post-truth is deeply connected to main developments of knowledge societies, and their intensifications along multiple axes and dimensions. These developments amount to tipping points or shifts to relations between technoscience and society and public uses of knowledge, indicating their increasingly political and politicised characters. Such shifts, variously displayed and analysed throughout the book, require discussion and re-articulation of some deeply held beliefs and assumptions about the role of knowledge and truth in public. They pose requirement for new starting points, in societal debates, for critique and academic analyses.