Issue 22 of Cell Notes, a serial publication of !%Promega Corp.%!, includes articles on screening for new chemical entities in academic settings, the use of noninvasive bioluminescent imaging to improve understanding of tumor biology, and a homogeneous luminescence-based assay for quantifying the glutathione content in mammalian cells. Among other topics discussed in the downloadable document are authenticating cell line identity, luminogenic enzyme substrates, and high-throughput screening and drug discovery at St. Jude Children’s Research Hospital.