DNA microarry, or DNA chip, technology is a new and powerful means of discovering, characterizing, and analyzing genes and their expression patterns. The potential of this technology is huge and its applications are widespread across many fields of biological and biomedical research. This manual assembles and synthesizes the expertise of over 30 innovators in this emerging field to provide detailed instruction on the design, construction, and applications of microarrays, as well as comprehensive descriptions of the software tools and strategies required for extensive image and data analysis.