Biophysics is the application of the analytical viewpoints, methods and/or instrumentation of physics to the investigation of biological problems. By this definition the domain of biophysics is limited only by the imagination of biophysicists, and ranges over areas such as molecular structure and energetics, motility, and membrane structure and assembly. Our principal professional organization, The Biophysical Society, reflects this variety with Special Interest Subgroups in such diverse areas as Motility, Membrane Structure and Assembly, and Bioenergetics.  Research in biophysics requires training in both the physical and the biological sciences.