Abstract Summary: MAPS is a MicroArray Project System for management and interpretation of microarray gene expression experiment information and data. Microarray project information is organized to track experiments and results that are: (1) validated by performing analysis on stored replicate gene expression data; and (2) queried according to the biological classifications of genes deposited on microarray chips. Availability: MAPS is accessible at http://www.dir.niehs.nih.gov/microarray/software/maps/ Contact: [email protected] * To whom correspondence should be addressed. 3 Present address: NimbleGen Systems, LLC, University Research Park, 505 South Rosa Road, Madison, WI 53719, USA.