Metabolites as Signals in Immunity and Inflammation describes the revolution in the definition of the word metabolism, highlighting changes in thinking about the whole field of immunology. These changes occur thanks to breakthrough experiments in basic research, and with the help of new technologies that allow for the testing of immunology hypotheses. In recent years, a substantial number of findings have been made around immunometabolism. What is emerging is a complex interplay between metabolic reprogramming and immunity, which is providing an extra dimension to our understanding of the immune system in health and disease.