Author Description

This book is the first to give a comprehensive account of subnormal subgroups of both finite and infinite groups. The authors trace the historical development of the subject from the early work of Wielandt, including the celebrated "join problem," to very recent results relating to the elusive subnormalizer of a subgroup. The book explains how the study of group rings can give a powerful and unified approach to major problems and encourages postgraduates and researchers in group theory and ring theory to further explore problems whose solutions remain incomplete.