More than 3,000 alphabetically arranged, cross-referenced entries cover men and women of science, as well as basic concepts and recent developments in life, Earth, and physical science. This 26-volume set (which includes the two annuals) contains more than 60 hands-on activities and 95 cross-referenced projects. Annuals include as many as 20 projects each. A reference volume includes a bibliography, index, scientific tables, and charts.