Though these balsa and glue models are really just more sophisticated versions of the ever popular balsa-wood plane kits, their construction calls for considerable patience and manual dexterity, and their successful flight depends on precise construction as well as the launcher's familiarity with aeronautical principles. Kaufmann combines a basic, though challenging, model with instruction in the fine points of lift, glide and balance and the design of accessories such as a thermal indicator. A good start on what promises to be a challenging project for the adept and experiment-oriented hobbyist.