"Most impediments to scientific understanding are conceptual locks, not factual lacks." The history of the discovery of the chaperonins and their role in protein folding provides a good illustration of this aphorism by Stephen J. Gould (1991). The pioneering experiments of Christian B. Anfinsen in the 1950s and 1960s revealed the remarkable finding that some pure denatured proteins will refold spontaneously into their biologically active three-dimensional structures when the denaturant is removed. They will do this in the absence of either an energy source or any other macromolecules. Thus was born an important corollary to the Central Dogma of molecular biology: the principle of self-assembly, according to which all the information required for each aminoacyl sequence to fold into its functional conformation resides within the sequence itself. It is hard to exaggerate the importance of this principle for our current understanding of the molecular basis of the living state. Just imagine the difficulties if each newly synthesized polypeptide chain required steric information from preexisting cellular components before it would fold correctly !