This issue of Science marks the publication of the first animal genome: the virtually complete sequence of the 97 million bases in the genome of a tiny nematode worm, Caenorhabditis elegans (see special section beginning on p. 2011). The early successes of worm sequencing were instrumental in convincing researchers and funding agencies of the value and feasibility of large-scale sequencing projects, and the two groups who sequenced the worm genome now expect to use the skills they9ve acquired to generate about half of the 3 billion bases in the human genome. Moreover, as the first sequence of a multicellular organism, the C. elegans genome should provide a cornucopia of biological information--and not just about the worm. Many of the genes researchers are finding in their studies of other organisms, including mammals, have their counterparts in the worm, and because the functions of many of the C. elegans genes are known--or soon will be--they can help provide insights into the development and function of the other organisms as well.