This presentation will give an overview of GCAM and examples of its application. GCAM is an integrated assessment model that is used widely for simulating the long-term growth in greenhouse gas emissions from human activities and for investigating the impact of emissions mitigation technologies and policies. GCAM has been used for the IPCC emissions scenarios, US climate science programs, and other climate change programs on understanding the role of technologies. The presentation will provide a description of the GCAM structure and examples of previous technology and policy studies.