Designed to complement the redesigned Traits of Life exhibit at the Exploratorium in San Francisco, this fine site allows visitors to view a photo gallery of the new exhibit, investigate some provocative online exhibits, and explore a host of links that are germane to the nature of biology. The exhibits constitute the core of the material available at the site, and are divided into four thematic areas, including "The Stuff of Life," "Life Needs Energy," "Making More Life," and "Change Over Time." "The Stuff of Life" is quite fascinating, as it profiles cells with a flair for the interactive. Users can learn about the workings of a cell through the "Cell Explorer" exhibit, read an interview with David Goodsell (a molecular biologist), and view a poster that describes how proteins make muscles work. The other three areas of online exhibits are similarly arranged and provide a host of educational materials that can be used as teaching aids or as compelling intellectual diversions.