My research is concerned with the structure and function of biologically active molecules. The structures are characterised using X-ray and/or neutron diffraction and their interactions with ligands is studied using molecular graphics. I work on both macromolecules and small molecule structures including inorganic compounds of interest. My book on Structure Determination with Mark Ladd is now in its 5th edition. Each successive edition has been extensively updated with respect to this quickly developing research tool.