Until recently, much research in language comprehension operated under the assumption that comprehenders initially identified the syntactic structure of sentences they were hearing or reading without regard to the meanings of the words in the sentences. A significant amount of recent work has challenged that position, however, and there is now abundant evidence that lexical information plays a central role in sentence processing. The papers in this special issue reflect the increased status on lexical representations in sentence processing research. The authors approach the question of the precise role of lexical information in sentence comprehension from a variety of theoretical perspectives. They supplement experimental psycholinguistic research with work in neighboring fields, including concepts and categorization, theoretical linguistics, and computational modeling. The volume should be of interest to psycholinguistics, cognitive scientists, linguistics and computer scientists.