In modern biology, there is an increasing emphasis on the relevance of the structure of a protein or other macromolecule to its biological functions. Similarly, the structure of a virus particle holds much information about its biology, and can be applied to such tasks as the interpretation of genetic data or the design of antiviral drugs. Recent technological advances in virus structure determination have allowed the structures of many viruses to be solved by x‐ray crystallography and/or cryo‐electron microscopy combined with image reconstruction. © 2003 American Institute of Physics