Psychological surveys find that substantial numbers of people regard themselves as shy (Zimbardo et al., 1975; Carducci, this volume, Chapter 11). However, it is only recently that shyness has attracted sustained research interest. The paucity of research in the past owes much to the domination of the study of individual differences in social behaviour by theories that prioritized the personality traits of extraversion and neuroticism, neither of which captures what is commonly understood by shyness. The neglect was perhaps more apparent than real, in that many of the concerns expressed by shy people were addressed in the psychological literature but were labelled in diverse ways, for example as reticence, social skills deficits or, more recently, social phobia. Nevertheless, willingness on the part of psychologists to embrace the ordinary language term shyness, notwithstanding the ambiguities involved in this, has stimulated interest in social anxiety. Because consideration of shyness and social anxiety is to be found in different branches of psychology, much of this research is published in separate journals and consequently is scattered. One of the goals of this volume is to bring together key representatives of diverse approaches to shyness.