The use of inducible gene expression systems is a developing area of plant molecular biological research. There is interest in the use of these systems as research tools, not only because they allow expression of genes which may be, for example, developmentally lethal, but also because they allow for controlled experiments to be performed in a true isogenic background. They also have the potential to provide a means by which desired characters are expressed in filled-based systems in the future. This text reviews the latest information on the wide range of promoter systems which have been developed in order to obtain external, inducible control of gene expression in plants. In 12 chapters, the systems which are currently in use are surveyed and their individual strengths and weaknesses are analyzed. Future developments in this area of research are foreshadowed. Written by experts from North America, New Zealand, Europe and Japan, this book should be reading for biotechnologists and of interest to all researchers and graduate students in plant genetics and molecular biology.