Professor Kewley has made fundamental advances in our understanding of the cosmic chemical and star-formation history of the universe. Her globally acclaimed research has proven critical to our understanding of how galaxies like our own Milky Way formed and evolved from the Big Bang to the present day. Her work exploits advances in multi-wavelength instrumentation and spectroscopy and combines new observations with the latest generation of theoretical models. These allow the power sources exciting the plasma in galaxies to be both reliably identified and physically characterized.