This document contains a report of the workshop held in Bonn, Germany, during the twenty-eighth session of the Subsidiary Body for Scientific and Technological Advice on the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). The workshop consisted of presentations given by experts from each of the Working Groups of the IPCC, addressing the science of climate change, mitigation, adaptation, and climate change and water. An informal discussion among Parties and experts from the IPCC on the contents of the Fourth Assessment Report was held on the same day