Book excerpt: Biological Rhythms and Photoperiodism in Plants brings together disparate subject areas into one accessible text of interest to all plant biologists. In this comprehensive volume, leading international researchers review our current understanding of circadian rhythms from a broad perspective. The book begins with a description of well known rhythmic processes such as gene expression, stomatal guard cell opening, and the movement of petals and leaves. Photoperiodic responses such as dormancy, bulbing, tuberization and flowering are then discussed in terms of their rhythmic behaviour. The latest data from current studies with mutant and transgenic plants is also included.