1) This is fine, first-hand book on the evolution of climate science over the last 30 years or so with nuanced descriptions of the science arguments and the difficulties in explaining science to policymakers and the public. Thank Stephen especially for the long campaign to regularize the uncertainty descriptions used in the IPCC 3rd and 4th Reviews. Other reviews have covered many of the topics I might have, so I won't repeat, but will offer something different.
2) If you want more history, start with:
Spencer Weart, The Discovery of Global Warming (New Histories of Science, Technology, and Medicine), which also has an equivalent website at the American Institute of Physics.
Then, read two of Stephen's earlier books:
Global Warming: Are We Entering the Greenhouse Century?, 1989. andLaboratory Earth the Planetary Gamble We (Science Masters), 1996.
This sequence offers a good look into what was known or not *at the time, not just by hindsight*, how real science works, and how scientists weigh data and competing hypotheses. Much of real science is trying to bound uncertainty, and good scientists change their minds. Some things that were theoretically very likely in 1989, but had not yet emerged from the noise into statistical significance, have long since done so.
3) If you want tutorials, here are my favorites, for 3 levels of background in ascending order
General audience, easily including high school, and inexpensive.
David Archer,The Long Thaw: How Humans Are Changing the Next 100,000 Years of Earth's Climate (Science Essentials), 2009. 180 easy pages. See my review over there for advice on figuring out whether or not someone might be an expert [like Archer] or not.
College undergrad textbook, for non-science majors, i.e., a little more math and science:
David Archer, Global Warming: Understanding the Forecast, 2008. Not so cheap, but good. 194 (denser) pages.
Serious, but the Real Stuff:
Search: ipcc wg i technical summary
for the ~70-page Technical Summary, what the scientists *really* think. Free. Anyone who has read SaaCS should understand why the Summary for Policy Makers is almost always weakened and uses obscure language compared to the TS. I hear this quite consistently from other IPCC authors, who are often amazed *anything* makes it into the SPM. Consider reading the TS for WG's II and III as well.
4) Bottom line:
So, SaaCS is a good book to read. Even better is to attend live talks by good climate scientists. Stephen is especially adept at giving talks for various backgrounds. There is no real substitute for listening to a real expert, watch them answer questions, and maybe even talk to them. In some places, that may be hard, but many good research universities offer public talks, and speakers may do outreach talks elsewhere.
Here in the SanFrancisco Bay Area, there must be at least 30+ IPCC authors around, and so many talks they sometimes have schedule conflicts. Among Stanford U, SLAC, UC Berkeley, LBNL, LLNL, various government groups, business organizations, and NGOs, anyone should be able to find a few good ones, *if they want to*.