Algebraic Number Theory - Frohlich, A. (University of London) a Taylor, M. J. (University of Manchester Institute of Science and Technology)

Here is a thorough treatment of the foundations of algebraic number theory which is built on to introduce more advanced ideas. The systematic development of techniques for the explicit calculation of the basic invariants is emphasised throughout. They combine theory with explicit computations and applications, giving motivation in terms of classical number-theoretic problems.