The human genome has been called the "blueprint of life," but it's really more of a parts list. Cellular architecture is better defined by its complexes, the molecular machines that actually make a cell, a cell. French researchers first coined the term " interactome" in 1999; the first protein-protein interactome data appeared in 2000. Today the field-like the 11-year-old it is-is maturing rapidly. Interactome research has racked up more than 560 publications, and databases now house interactions numbering in the hundreds of thousands. Still, as international efforts to map the human protein-interaction network get under way, it's clear interactomics has a long way to go. By Jeffrey M. Perkel