
 Nat' Academies Press, Biographical Memoirs V.63 (1994) 
  In addition to the usual theory of Banach spaces and linear transformations, Hille was able to organize into a unified whole the calculus of vectorvalued functions, function theory for vectorvalued functions, and the operational calculus. 
  The theory of commutative Banach algebras is introduced early in the book and plays a major role in the chapters on spectral theory and holomorphic semigroups. 
  The influence of Yosida and, to some extent, Feller is quite evident; and of course I took advantage of my being coauthor by including my own results on extended classes of semigroups (distinguished by their behavior at the origin) and their generating theorems, perturbation theory, the adjoint semigroup, the operational calculus, and spectral theory. 
 www.nap.edu /openbook/0309049768/html/218.html (3438 words) 
