This report is concerned primarily with developments in the dynamical theory of synoptic and mesoscale motions in the atmosphere, excluding clouds. The areas in which there has been a major effort may be roughly classified as baroclinic instability, gravity waves and related problems, planetary waves (studies leading to a theory of the equatorial quasi-biennial oscillation), atmospheric tides, some consideration of sea breezes, and, finally, acoustic gravity waves. Advances in the theory of the formation of fronts have been reported elsewhere. Much of this material is related to cognate studies in fluid dynamics that cannot be reviewed here (e.g., convection in a rotating annulus) and some arbitrary selections have been made. In some instances reported contributions were made by visitors to the U.S. and should in part be ascribed also to other national programs.