technology, which began in earnest about 15 years ago. Today, we can routinely do experiments that were inconceivable in the early 1970's. Only comparatively simple technology available even in small laboratories is required to synthesize a gene and from it, to produce vast amounts of biological materials of enormous commercial value. These technical developments and others have stimulated increased activities in the field of enzyme biotechnology, using enzymes to catalyze "unnatural" reactions to produce complex molecules with stereochemical precision. It is true today, we can readily produce DNA fragments that will encode any amino acid sequence that we might desire, but at this point, our foundation of basic knowledge falls short. The dream of "designer enzymes" is still a fantasy, but the current wave of research activity and exciting new developments suggest that in the future the dream may become a reality.