A grand challenge in the post-genomic era is a complete computer representation of the cell, the organism, and the biosphere, which will enable computational prediction of higher-level complexity of cellular processes and organism behaviors from genomic and chemical information. Towards this end we have been developing a bioinformatics resource named KEGG, Kyoto Encyclopedia of Genes and Genomes, as part of the research projects in the Kanehisa Laboratory of Kyoto University Bioinformatics Center.