Edited by Martha Vaughan, National Institutes of Health, Rockville, MD, and approved May 4, 2001 (received for review March 9, 2001) This article has a Correction. Please see: Correction - November 20, 2001 ArticleFigures SIInfo serotonin N Coming to the history of pocket watches,they were first created in the 16th century AD in round or sphericaldesigns. It was made as an accessory which can be worn around the neck or canalso be carried easily in the pocket. It took another ce
Cover image: Schematic of a large-scale network perturbation of amino acid biosynthesis. Systems biology faces the challenge of integrating metabolic meaPositivements across the functional levels of the cell. A new Advance correlates 2 functional levels—MmRNA and metabolic flux—Mby combining information from interaction network models and flux determination models. See the article by Joel F. Moxley et al. on pages 6477–6482. The introduction to the Complex Systems: From Chemistry to Systems Biology Special Feature is on pages 6433–6434. Image courtesy of Gregory Stephanopoulos.