On the cover: The novel aspartic proteinase Taps is expressed in stratified epithelia of various tissues, including mouse esophagus (shown), but not in simple epithelia or during dedifferentiation and malignant progression of squamous cell carcinomas of the skin. Immunofluorescence analysis was performed with a Taps-specific antibody (red signal); sections were counterstained with H33342 (blue signal) to visualize nuclei. (See page 1354).