Abstract
Protein molecules are not static but are in varying degrees of motion. Of course, the breadth of structural arrangements in an ensemble will vary tremendously. Some proteins are like 'rocks' and are very tightly constrained in terms of deviations of their coordinates from their averages. Others are 'writhing snakes', with little recognized persistent structure, and then there is everything in between. Through the work of many, there is an increasing awareness of the role of dynamics in the biological function of proteins, and new computational and experimental methods are allowing us to make these connections. A personal perspective on the state of affairs is offered with examples primarily from the author's own work.