The book provides an overview of exciting recent developments and advances in our understanding of the role of clouds in climate and atmospheric chemistry. Topics covered include: Modeling of clouds in GCMs Observations of the microphysical properties of clouds The water vapor cycle Troposphere/stratosphere exchange The role of clouds in tropospheric ozone The regulation of current and paleoclimate by clouds Radiative/convection interactions Anthropogenic sulfate aerosols and the modification of cloud properties.