InhaltsangabeForeword.- Origins of Cometary Materials.- Origin of Comet Nuclei and Dynamics.- Reservoir for Comet Material: Circumstellar Grains.- Interstellar Reservoirs of Cometary Matter.- Cometary Refractory Grains: Interstellar and Nebular Sources.- Dynamical Origin of Comets and Their Reservoirs.- Reservoirs for Comets: Compositional Differences Based on Infrared Observations.- Thermal and Chemical Evolution of Comet Nuclei and Kuiper Belt Objects.- Loss of the Surface Layers of Comet Nuclei.- Distributed Sources in Comets.- How Well Do Experimental Results on Large Samples of Gas-Laden Amorphous Ice Duplicate Deep Impact's Findings?.- Comet Knudsen Layers.- Morphology-Composition-Isotopes: Recent Results from Observations.- Deep Impact and the Origin and Evolution of Cometary Nuclei.- Assessing the elemental composition of comet 81P/Wild 2 by analyzing dust collected by Stardust.- Composition Measurements of a Comet from the Rosetta Orbiter Spacecraft.- Capabilities of Philae, the Rosetta Lander.- Rapporteur Paper on the Composition of Comets.- The Contributions of Comets to Planets, Atmospheres, and Life: Insights from Cassini-Huygens, Galileo, Giotto, and Inner Planet Missions.