The origins and distribution of atlatls, and theirHistorical reenactment historical persistence, are discussed. The simplest physical principles are presented: the atlatlAtlatl, atlatlist acts like a leverLever, so theLaunch speed launch speedSpeed of its dartDart projectileProjectile exceeds that of the same dartDart thrown without the aid of the atlatlAtlatl, atlatlist. Refinements (such as thrower body motionMotion, and flexible dartDart shaftShaft)Shaft require more subtle physics. The nature of approximationsPhysics approximations in physics is outlined and the case made for their usefulness for all of the ancient projectileProjectile weapons examined in this book. The significance of atlatls in MesoamericaMesoamerica, Mesoamerican at the time of the Conquest is summarized.