This book, intended for research mathematicians, proves the duality theorems that have come to play an increasingly important role in number theory and arithmetic geometry, for example, in the proof of Fermat's Last Theorem.

Reviews of the first edition
The book deals with duality theorems in Galois, étale and flat cohomology, for local and global fields, as well as the corresponding rings of integers. Also covered are results about cohomological dimension, finiteness and Euler-Poincaré characteristics. It can serve as a good general reference for these questions.
Mathematical Reviews, Gerd Faltings.

… However, much of this work [by Tate, Artin, Verdier, and others] was never published in details. The main purpose of the book under review is to offer a selfcontained and systematic treatment of these developments.
Zentralblatt MATH, L. Badescu.