Leading scientists in gene expression methodology and bioinformatics data analysis describe readily reproducible methods for measuring RNA levels in cells and tissues. The techniques presented include new methods for applying the Affymetrix GeneChip®, SAR-SAGE, StaRT-PCR, SSH, the Invader Assay®, and ADGEM. The authors also provide critical bioinformatics insight and resources for data analysis and management. By distilling the basic underlying principles of many methods to a few straightforward concepts, investigators can easily choose the method most appropriate to their application.