This book describes the crucial role of "zinc signals" in biological processes on a molecular and physiological basis, discussing future directions and questions underlying this unique phenomenon. To accomplish this, a group of worldwide leaders in the field, who have made outstanding contributions, overview zinc signals from a professional standpoint. Zinc plays an indispensable role in various cellular processes. It regulates a great number of protein functions including transcription factors, enzymes, adapters, and growth factors as a structural or catalytic factor or both. Recently, another function of zinc has received extensive interest and attention because of its potential importance as a signaling mediator. Zinc plays a dynamic