The control of plant gene expression at the transcriptional level is the main subject of this volume. Genetics, molecular biology and gene technology have dramatically improved our knowledge of this event. The functional analysis of promoters and transcription factors provides more and more insights into the molecular anatomy of initiation complexes assembled from RNA polymerase and the multiplicity of helper and control proteins. Formation of specific DNA-protein complexes – activating or repressing transcription – is the crux of developmental or environmental control of gene expression. The book presents an up-to-date, critical overview of this rapidly advancing field.