  This paper is an introduction to the state sum model for the Alexander-Conway
polynomial that was introduced in the the author's book "Formal Knot Theory"
(Princeton University Press, 1983). The article outlines how Alexander's
original definition of the polynomial as the determinant of a matrix associated
with the link diagram can be reformulated as a state summation over
combinatorial configurations of the diagram. Facts about the state model, the
Clock Theorem (that makes this model tick) and relations with other state
models such as the bracket polynomial, are discussed. The paper includes a
miniature introduction to Khovanov homology. This paper will appear in the
forthcoming Dover republication of Formal Knot Theory.
