This research was supported in part by the Santa Fe Institute, The Center for Nonlinear and Complex Systems at Duke University, Provost's Common Fund, and NSF Grant EAR-89-15983. It grew from Stuart Kauffman's discussion of the NK landscape model at the Santa Fe Institute's 1991 Complex Systems Summer School. I thank: Peter Haff, Marcy Uyenoyama and Richard Palmer for computational support; Joe Felsenstein, Frank Eeckman, Günter Wagner and Eric Mjolsness for the invitations to speak which facilitated this work.