<P>Computer simulation has become an important means for obtaining knowledge about nature. The practice of scientific simulation and the frequent use of uncertain simulation results in public policy raise a wide range of philosophical questions. Most prominently highlighted is the field of anthropogenic climate change—are humans currently changing the climate? </P><P>Referring to empirical results from science studies and political science, <STRONG>Simulating Nature: A Philosophical Study of Computer-Simulation Uncertainties and Their Role in Climate Science and Policy Advice, Second Edition</STRONG> addresses questions about the types of uncertainty associated with scientific simulation and about how these uncertainties can be communicated.</P><P>The author, who participated in the United Nations’ Intergovernmental Panel on Climate Change (IPCC) plenaries in 2001 and 2007, discusses the assessment reports and workings of the IPCC. This second edition reflects the latest developments in climate change policy, including a thorough update and rewriting of sections that refer to the IPCC.</P>