Most advanced second language (L2) learners find continued vocabulary growth to be one of the most difficult areas in second language learning, and vocabulary acquisition has not received little attention by researchers. As a result, no unified theory of L2 vocabulary acquisition exists, although the literature contains ample advice on how to teach vocabulary. Presently, the most promising approach to constructing a theory of L2 vocabulary learning appears to come from the field of cognitive psycholinguistics. The approach posits that new words are stored in the brain through associate networks that link a word to other semantically related words and concepts, and relate it syntactically to appropriate structures. Visual imagery is also very important in the association process. It appears that humans associate one or more images with each word designating a concrete object, concept, or abstract idea. Therefore, L2 vocabulary acquisition is much more complex than it appears on the surface, involving many different faculties. A 17-item bibliography is included. (MSE)