Algebraic number theory

A. Fröhlich, M. J. Taylor9780521366649, 9780521438346, 052136664X, 0521438349

This book provides a brisk, thorough treatment of the foundations of algebraic number theory on which it builds to introduce more advanced topics. Throughout, the authors emphasize the systematic development of techniques for the explicit calculation of the basic invariants such as rings of integers, class groups, and units, combining at each stage theory with explicit computations.