Describes a classroom exercise that uses a letter from Max Delbruck to George Beadle to stimulate interest in the mechanics of a nonoverlapping comma-free code. Enables students to participate in the rich history of molecular biology and illustrates to them that scientists and science can be fun. (JRH)

This revision of the "Basic/Essential Skills Taxonomy" exhibits changes based on use of the original taxonomy in the field. It features more precise definitions of the levels of key words and phrases, the deletion of some science items that ranged above basic skills, the combination of the language arts sections from the original two parts, and…