This volume contains the refereed proceedings of the International Conference on Abelian Groups and Modules held at the Dublin Institute of Technology in Ireland, from August 10 until August 14, 1998. The meeting brought together more than 50 researchers and graduate students from 14 countries around the world. In a series of eight invited survey talks, experts in the field presented several active areas of research, including: · Almost completely decomposable abelian groups, Butler groups and almost free groups - the classification problem, and invariants of special classes of torsion-free abelian groups. · Totally projective groups, their automorphism groups and their group rings - questions about unique passage between these categories. · Radicals commuting with products. · The Ziegler spectra of Neumann regular rings and the class (semi-) groups of Prüfer domains. · The Krull-Schmidt property for valuation domains. These main talks were accompanied by many other presentations of current research on abelian groups and modules. Methods from model theory, category theory, infinite combinatorics, representation theory, classical algebra and geometry were applied to the study of abelian groups and modules; conversely, results and methods from abelian group theory were applied to general module theory and non-commutative groups. All this is reflected in the 30 articles in this volume, which introduce the reader to an active and attractive part of algebra that over the years has gained much from its position at the crossroads of mathematics. Lively discussions at the conference influenced the final work on the presented papers, which convey some sense of the intellectual ferment they generated and stimulate the reader to consider and actively investigate the topics and problems contained therein.