This book is aimed at the general public and has been percolating in my head since mid-2006. It is not intended to be a textbook, but rather an accessible overview of what we know and don't know about climate change, what options we have to reduce greenhouse gas emissions in the energy sector of our economy, and what policies we should and should not adopt to make progress.

I am a latecomer to the climate and energy field. My career has been in physics. I received my PhD in 1956 and my Nobel Prize in 1976 at the relatively young age of 45. Many Nobel Laureates continue research, but some look for other mountains to climb, and I was one of those. I took on the job of directing a large Department of Energy scientific laboratory at Stanford University in 1984; its mission is to build and operate unique, large-scale research tools for the national scientific community. During my 15 years as director we expanded opportunities in many areas; the number of users from outside Stanford that came to the laboratory rose from about 1000 to nearly 3000, and the facilities that we pioneered were reproduced in many parts of the world.

Like many scientists, I had followed the growing debate on climate change from a distance, though I did have some peripheral involvement in related areas having to do with energy options.