The final volume of James Clerk Maxwell's correspondence and manuscript papers covers the years 1874-1879, during Maxwell's Cambridge Professorship, his directing of the Cavendish Laboratory, and his work as writer and editor. His letters show his response to innovations in physical theory--by Boltzmann, Gibbs, Lorentz, and van der Waals--and further explorations in statistical physics and the kinetic theory of gases. His letters reflect his influence...