This issue contains five articles dealing with several aspects of linguistic theory. The first, "Origine et evolution de la notion de 'situation' de 'l'Ecole linguistique de Londres': de Malinowski a Lyons," examines the origin and meaning of the concept of "situation" in articles by the London school of linguists. The second, "Some Aspects of a Semantic Taxonomy," discusses conditions required for structural description of linguistic content. The third defines "vigilant memory" and its application to the segmentation and error-correction of natural language input. A description of the mechanical translation system developed at the Universite de Montreal includes discussion of the theory, computer system, steps in translating, and future prospects. The last article, "Universal Quantifiers and Entailment," explores the relationship of reason and condition clauses. (RL)