This Special Issue of Cybernetics and Human Knowing contains rare material related to G. Spencer-Brown's book Laws of Form and its contents.

In 1973 there was a conference at Big Sur at which Spencer-Brown discussed his calculus with a group of scientists. This was the AUM Conference at Esalen, and the scientists consisted in an assortment of remarkable individuals exploring the cutting edge of human consciousness and culture, including Alan Watts, Ram Dass, John Lilly, Heinz von Foerster, Kurt von Meier, and others. One of the participants, Walter Barney, has written about this conference and has long been a keeper of the transcripts of Spencer-Brown's talks. In this issue we print Barney's transcripts of the conference and an article by Walter Barney and Kurt von Meier reflecting on the AUM conference. The transcripts are a remarkable amalgam of the thinking of Spencer-Brown and the questions and comments of the participants in AUM. The transcripts carry the same lucidity that infuses Laws of Form.

The other articles in this issue include a paper on Flagg Resolution by James Flagg and Louis Kauffman, a paper on Paper Computers and the Emergence of Fermions by Louis Kauffman, and a Virtual Logic Column by Louis Kauffman that is a new take on the Barber paradox and the Russell Paradox, based on satire, mirrors, and the key observation of Douglas Harding that no person can (in the absence of mirrors) perceive his or her own head. There is an American Society for Cybernetics Column by Zane Gillespie about the structure of implausibility in music, art, and cybernetics.