L. C. Ho, Observatories of the Carnegie Institution of Washington

Acknowledgments are also due to our many colleagues who willingly contributed figures and discussions of the issues involved in this report. The research described herein was carried out in part by the Jet Propulsion Laboratory, California Institute of Tech-nology, under a contract with the National Aeronautics and Space Administration. Reference herein to any specific commercial product, process, or service by trade name, trademark, or manufacturer, does not constitute or imply its endorsement by the United States Government or the Jet Propulsion Laboratory, California Institute of Technology. 1 Executive Summary Extending the capabilities of NGST into the mid-infrared (MIR) would vastly enhance the ability of the observa-tory to resolve key scientific questions. The areas most directly impacted by an MIR capability on NGST include the genesis and evolution of galaxies, the nature of lumi-nous galactic nuclei, the star formation process, the life cycle of dust grains, the evolution of circumstellar partic