It is widely recognized that the static structures of proteins yield substantial insights into how they function. It is also widely understood that considerable atomic motion takes place in proteins. A protein is not the single structure suggested by the static pictures, but rather consists of multiple structures interconverting on various time scales. This rich dynamical nature is crucial to understanding protein function but very little is really understood quantitatively about protein dynamics. The reason for this is that motions on a broad time scale, from femtoseconds to minutes, can be important, but there are both experimental and theoretical challenges in characterizing motion on such a broad time scale. It will first be discussed how the development of new experimental approaches in our lab and our collaborators, (1) initiating structural transformation in chemical systems (like laser induced temperature jumps and fast mixing devices) and (2) spectroscopic probes of structure (like time-resolved isotope-edited IR spectroscopy), permit the experimental characterization of atomic motion within proteins from 10 ps to minutes with considerable structural specificity. Then some specific studies on enzyme systems, focusing on lactate dehydrogenase, will be discussed relating dynamics to function.