Interstellar clouds near the sun

Present knowledge concerning interstellar clouds near the sun is reviewed. The distribution and chracteristics of this interstellar dust and gas are described, and interstellar wind flowing through the solar system is discussed. Evidence is presented for a flow of more distant interstellar material past the solar system. Possible effects of an encounter between the solar system and a cloud core embedded in this low-density flow are examined. It is likely that the solar system is heading for condensations within 100 pc and that encounters may occur in the next 0.1 to 1 Myr. Such encounters could trigger global weather effects, including surface cooling and increased precipitation.