Technological innovation can lower the cost of achieving environmental objectives, so it is important to understand how environmental policy design and technological innovation are linked. This is particularly true in the area of climate change where the estimated future costs of reducing greenhouse gas emissions are affected greatly by the technological trajectory of the economy. While we suspect that public policy can play an important role in accelerating the development and diffusion of climate change mitigation and adaptation technologies, empirical evidence in this area remains scant. This book presents a series of papers that explore the extent to which technological innovation can lower the cost of achieving climate change mitigation objectives.