Annotation Featherston (Eberhard-Karls-U., Tubingen) presents the results of three experiments on the role of empty categories--phonetically null place-holders for locally absent constituents--in sentence processing. The experiments used probe recognition, sentence matching, and event-related potentials, as well as self-paced reading. Coverage includes a discussion of the predictions of both Principles and Parameters Theory and Head-Driven Phrase Structure Grammar. Annotation c. Book News, Inc., Portland, OR (booknews.com).