As Congress considers legislation to reduce the greenhouse gas (GHG) emissions that contribute to climate change, attention has focused on "cap-and-trade" legislation. Such legislation would set a national cap of GHG emissions, with allowances to emit limited amounts of the gases distributed or auctioned to affected parties. Recently, there has also been discussion of taxes on greenhouse-gas-emitting substances, which proponents argue would provide greater transparency and a clearer price signal. This book examines the proponents of legislation who counter that the threat of climate change is too important for action to be delayed, and that energy-efficiency and lower GHG emissions can be the building blocks of a program to restore the economy as well as to protect the environment.