Recent years have witnessed a quiet revolution in biology as seemingly disparate fields, as far apart as biophysics and medical specialties such as human genetics and cardiovascular diseases, have begun to merge. Studies of molecular chaperones have bridged the gaps between biophysics and medical genetics, and they provide a clear example of promise of the new synthetic approach. Biophysicists, using nuclear magnetic resonance spectroscopy and other techniques in cell-free systems, have elucidated some of the basic mechanisms of protein folding, and they have shown that chaperone proteins participate in multiple steps in the folding pathway of model substrates (Dobson and Ellis 1998; Richardson et al. 1998). Microbial geneticists and cell biologists have also found that similar chaperones also act in off-pathway events such as aggregation and protein degradation (Ciechanover 1998; Glover and Lindquist 1998). Meanwhile, medical scientists have become acutely aware that protein aggregates and protein damage are significant factors in the pathogenesis of heritable diseases such as cystic fibrosis and of acquired disorders such as ischemic strokes and heart attacks (for a review, see Thomas et al. 1995; Benjamin and McMillan 1998). In addition, the degree of aggregate formation in a cell can often be modified by the expression of specific chaperones, suggesting a possible avenue to alter the phenotype of many human pathological states. Because several chaperones are also heat shock proteins (HSPs), the well-established cytoprotective and regulatory properties of HSPs may be exploited as therapeutic targets for similar disorders.