Badger is well known for his original contributions which have mainly been made in the field of the aromatic and polycyclic organic compounds. His research activities along these lines began almost twenty years ago when he became associated with Professor Cook at the University of London, the collaboration being continued later at the University of Glasgow. During the course of this work attention was focussed on some polycyclic compounds which showed marked carcinogenic effect, notably benzpyrene, and Professor Badger has made significant contributions to our knowledge in this field. He has also contributed to our knowledge of the absorption spectra of certain groups of organic compounds, and has devised interesting and successful methods for the synthesis of higher fatty acids.