Arch wires are considered to be backbone of orthodontics.This book provides an in depth exploration of arch wires including their shape, material, and characteristics and how these factors affect treatment outcomes.The development of an effective orthodontic force system requires knowledge of mechanics, biomaterials, and their interaction. Arch wires are the foundation of these appliances and are selected in size, material, properties, and bent to deliver the desired force.The ideal arch wire should be designed to move teeth with light continuous forces and behave elastically over a period of weeks to months.The chapters demonstrate the evolution of arch wires technology from conventional stainless steel to contemporary choices like-Copper NiTi, TMA wire, etc.The success or failure of many forms of treatment depends upon correct selection of wires, possessing adequate properties, combined with careful manipulation.The recent advancement in materials have changed rapidly in the recent years and will continue to do so in the future.