These lecture notes, presented as a tutorial at the Euroconference on Moder
n Trends in Electrochemistry of Molecular Interfaces, consist of the follow
ing sections: (i) elementary transition state theory of reaction rates; (ii
) elementary ion solvation theory; (iii) elementary solvent reorganization
theory; (iv) generalizations; (v) extension to the metal/liquid interface;
(vi) extension to the liquid I liquid interface, and (vii) examples of refe
rences (C) 2000 Elsevier Science S.A. All rights reserved.