Nernst, the historiography of his science, and its context -- Nothing is more practical than theory: beginnings -- The early researchers -- The Göttingen years -- The Nernst-Planck exchange -- Electricity and iron: the electrolytic lamp -- High temperatures and the heat theorem -- Theory and the heat theorem -- Berlin: low temperatures -- The incorporation of quantum theory -- "The witches's sabbath": Nernst and the first International Solvay Congress in Physics -- Simply a matter of chemistry? The Noble Prize.