Molecular Cell is a companion to Cell, the leading journal of biology and the highest-impact journal in the world. Launched in December 1997 and published monthly, Molecular Cell defines the field of molecular biology with a relatively small number of significant papers, up to 15 articles per issue. Coverage will extend from structure to human diseases, concentrating on molecular analyses. Topics that will be represented in the first issues include gene expression, RNA processing, replication, recombination and repair, structure, chaperones, receptors, signal transduction, cell cycle, and tumorigenesis.