John Brockman, writer and editor, created a website called Edge (edge, or boundary) in which a conversation takes place between the academic world and an intellectually curious audience. That page was classified in the same category as magazines such as The New Yorker and The Economist. Brockman considered himself heir to the artist J. L. Byars, who last century organized a club of very diverse thinkers and said that to reach the edge of knowledge one had to ask others the questions they ask themselves.

Discussions in Edge could be collected today in a manuscript of more than ten million words. One of his initiatives was the annual publication of a book with various answers to a great question he asked. This year, to celebrate twenty years of the initiative (and to close it), Brockman decided not to ask a question, but to ask each participant for his, that last unknown that won't let him sleep. The book has more than 300 pages; each has only a brief question printed and the name of the one who asks it. Natural and social scientists, writers, artists and entrepreneurs participated.