Incommensurate Phases in Dielectrics'' has been divided into two volumes. Volume 1 treats the macroscopic and microscopic theory of incommensurate systems and provides a review of the experimental techniques used to study the new phenomena. Volume 2 presents specific results obtained for some of the most representative systems currently investigated. Whilst the chapters comprise broad, up-to-date reviews on these systems, they also contain important results of the contributors who are actively engaged in research in the field.