Brian W. Matthews is a biochemist and biophysicist educated at the University of Adelaide, contributor to x-ray crystallographic methodology at the University of Cambridge, and since 1970 at the University of Oregon as Professor of Physics and HHMI investigator in the Institute of Molecular Biology. He created hundreds of mutants of T4 lysozyme (making it the most common structure in the PDB), determined their structure by x-ray crystallography and measured their melting temperatures. Starting from questions about the basis of "temperature-sensitive" mutations, his work has explicated much about the general energetic and structural effects of mutations in proteins. He also solved early structures of the thermophilic bacterial enzyme thermolysin, the helix-turn-helix DNA-binding transcription factor lambda Cro repressor, and the light-antenna bacteriochlorophyll protein. Beyond his contributions to biochemistry, Matthews is also known in the machine learning community for the Matthews correlation coefficient, which he introduced in a paper in 1968. The coefficient is used as a measure of the quality of binary (two-class) classifications. Matthews has been a member of the National Academy of Sciences since 1986. He was the editor of the scientific journal Protein Science.