The theory of conventional metaphor, as developed by Lakoff and Johnson (1980) is briefly recapitulated. The implications of this theory for teaching English for Specific Purposes are outlined. Chief among these cannot be accurately understood if the metaphorical chaining is not retracted; and (2) the ability of metaphor to add lexis that is not normally thought of as pertaining to the field in question. A plea is made for a field-by-field study of the role of metaphor in ESP texts. (Author/JL)