AbstractA review is presented of research on several aspects of the dynamics of conformational transitions in polymers. Brownian dynamics computer simulations of polymer chains show that transitions occur frequently in a correlated fashion involving cranklike counterrotation of two parallel bonds. Theoretical analysis brings out the importance of such counterrotations in creating a localized mode by which the transition can proceed without excessive motion of the whole molecule. The correlated motions are reflected in time correlation functions, which take on a character reflecting diffusion of the information about the initial state. Finally, several experiments are cited that can be explained on the basis of this picture of the mechanism of con formation a! transitions.