  This paper is an introduction to Khovanov homology, starting with the
Kauffman bracket state summation, emphasizing the Bar-Natan Canopoloy and
tangle cobordism approach. The paper discusses a simplicial approach to
Khovanov homology and a quantum model for it so that the graded Euler
characteristic that produces the Jones polynomial from Khovanov homology
becomes the trace of a unitary transformation on a Hilbert space associated
with the Khovanov Homology.
