His research interests are in understanding how the arrangements of atoms in solids determine how the material functions, chemically or physically, and for the development and teaching of techniques for those studies. To do this, he works on software and instrument development as well as conducts measurements and analyzes the results. Brian has developed several novel software concepts: the first fitting program for PDFs for study of local order in crystalline materials and the first multi-field boolean search (a.k.a. PDF-4) application for powder diffraction databases. His best known programs include GSAS-II, CMPR, CIFTOOLS (pdCIFplot) and EXPGUI.