Over the last 40 years or so, there has been significant work on the dynamics and aerodynamics of entry vehicles. Recently with missions to various planets, like Mars some of these issues have needed to be revisited. New requirements such as aeroassist and precision landings have required improved understanding of the dynamics and their relationship to the aerodynamics of these vehicles. This talk will review the basic mechanics of entry with emphasis on the various aerodynamic parameters that shape these trajectories. Particular attention will be given to the high supersonic to transonic speed range where parachute deployment issues arise. Here the emphasis will be on the pitch damping which are very nonlinear with angle of attack. These nonlinearities can lead to limit cycle types of behavior. A simple approximation to limit cycle behavior will be discussed.