Written and edited by experts in the field, this collection from Cold Spring Harbor Perspectives in Biology examines the molecular bases of different plant characteristics and how they can be manipulated genetically using modern molecular biological techniques. The contributors review recent advances in our understanding of plant plasticity, circadian rhythms, stomatal development, inflorescence architecture, symbiotic phosphate acquisition, and specialized plant metabolism and discuss how this knowledge might be used to boost yields, improve tolerance to pathogens and environmental stress, and enhance nutritional content. Several chapters are devoted to the development of specific genetically modified plants (e.g., disease-resistant cassava and submergence-tolerant rice) and their agronomic and socioeconomic impacts.