Mark Levene undertook a PhD within the Database group at Birkbeck College, University of London. His PhD was in the area of Complex Objects and Nested Relational Structures, a theory which is providing an underpinning for XML data modeling and querying. On completing his PhD in 1990, Dr. Levene joined the Computer Science Department at University College London as a lecturer. He continued to research relational databases, specialising in the area of incomplete information, and in 1994 started working on web interaction and the navigation problem in hypertext. He was promoted at UCL to Senior L...