Priscilla Walmsley is a software architect at Vitria Technology, Inc. Previously, she was co-founder and VP of Research for XMLSolutions Corporation, where she researched and prototype XML-based software. Ms. Walmsley has extensive technical and subject matter expertise in the areas of electronic commerce, enterprise application integration, and data management. She is the author of Definitive XML Schema (December, 2001, Prentice Hall). She can be reached at firstname.lastname@example.org.