This special issue arose out of a symposium on metaphor and artificial intelligence in which the main orientation was computational models and psychological processing models of metaphorical understanding. The papers in this issue discuss: *implemented computational systems for handling different aspects of metaphor understanding; *how metaphor can be accommodated in accepted logical representational frameworks; *psychological processes involved in metaphor understanding; and *the cross-linguistic cognitive reality of conceptual metaphors. Table of Contents John A. Barnden and Mark G. Lee: Introduction. Michael S. C. Thomas and Denis Mareschal: Special Issue on Metaphor and Artificial Intelligence. Metaphor as Categorization: A Connectionist Implementation. 5 Mark G. Lee and John A. Barnden: Reasoning About Mixed Metaphors Within an Implemented Artificial Intelligence System. 29 Heather Bortfeld and Matthew S. McGlone: The Continuum of metaphor processing 75 Frank Brisard, Steven Frisson, and Dominiek Sandra: Processing Unfamiliar Metaphors in a Self-Paced Reading Task. 87 Ira A. Noveck, Maryse Bianco, and Alain Castry: The Costs and Benefits of Metaphor. 109