Small-angle X-ray scattering (SAXS) has emerged as an important method for studying large-scale dynamic processes, ranging from protein folding to virus particle polymorphism. The renaissance of this method has resulted from a variety of advances in molecular biology and X-ray instrumentation, and these have dramatically increased the information content of the derived results. Modern synchrotron X-ray sources and advanced detector systems have lead to higher-resolution data in both the spatial and time domains. The purpose of this chapter is to address practical aspects of SAXS as they relate to and complement macromolecular crystallography. Keywords: data collection; data processing; protein folding; small-angle X-ray scattering; solution X-ray scattering; synchrotron radiation; time-resolved studies