Entries vary in length from 250 to 2,500 words. Longer articles are divided by subheadings, adding to clarity. As is common format for UXL publications, extensive cross-referencing directs users to related articles, and sidebars define "Words to Know." Most of the photographs and technical diagrams are in color, a definite improvement over the previous edition's all black-and-white illustrations. Among the new entries are DVD technology and Internet.

It difficult to find fault with this clearly written resource that uses simple, nontechnical terms to explain scientific concepts at a basic level. Its A-Z format distinguishes it from other multivolume science sets for a similar age group, such as The New Book of Popular Science (Grolier, 2000) and The World Book Encyclopedia of Science (World Book, 2001), which have a topical arrangement. Visually appealing and user-friendly, UXL Encyclopedia of Science is sure to find success with beginning researchers and is recommended for middle-school and junior-high-school students and the libraries that serve them.