Climate Change 2001: The Scientific Basis  (Intergovernmental Panel on Climate Change).
This is the Bible on climate science. It is a peer-reviewed, review-of-literature consensus compendium of all the science, updated every five years. It is a collaboration of many hundreds of scientists of established professional standing in climate-related disciplines. Wikipedia . Press Contact .
Climate Change Science: An Analysis of Some Key Questions  (National Academies' National Research Council, 2001).
Upon taking office, Bush administration doubters asked the prestigious (and non-foreign) NAS to double-check and second-guess the IPCC's 2001 findings. Result: the NAS confirmed most of the key points.
Understanding Climate Change Feedbacks  (National Academies' National Research Council, 2003).
The climate system is immensely complex because of the many "feedbacks" between climate itself, the oceans, the biosphere, the ice sheets, and atmospheric phenomena like clouds and particulates. The report explores these processes which raise uncertainty in climate modeling — they could make global warming better or worse. It chronicles the many recent advances in understanding of feedbacks.
Climate Crash: Abrupt Climate Change and What It Means for Our Future  (National Academies, 2005).
The fossil record of ancient climate suggests that some climate change happens abruptly, rather than gradually as our basic models predict. This report explores some of the many processes, like ocean currents, which could cause abrupt change. One implication is that our generation could discover that we have less time than we think to address manmade greenhouse warming.
U.S. National Assessment of Climate Change. 
This comprehensive study of the vulnerabilities and potential impacts of climate change on the U.S. was mandated by the Global Change Research Act of 1990. It includes studies looking specifically at 19 different U.S. regions. Assembled by hundreds of experts from academia and elsewhere, it was completed in the late Clinton administration and partly suppressed by the Bush administration.