Enzymes, solids, and homogeneous solution systems have all been known to display catalytic activity for over 100 years. However, the fields of homogeneous, heterogeneous, and enzymatic catalysis have developed almost independently. Until recently, seldom have the practitioners of one of these areas had contact with, much less worked in, the other disciplines. Nevertheless, we feel that there is much to learn from the juxtaposition of information and ideas from these seemingly disparate areas of study. The previous chapter discusses the relationship between homogeneous and enzymatic catalysis. The specificity and high reactivity characteristic of enzymes and homogeneous catalysts make the comparison seductively simple. However, it is the contention of the short discussion in this chapter that the similarities between enzymatic and heterogeneous catalysis are at least as great as, if not greater than, those between enzymatic and homogeneous catalysts. Moreover, the thinking developed in one of these fields has potential to impact the other in an efficacious way and to generate creative approaches [1-5].