Advocates of critical realism often refer to the importance of "the logic of analogy and metaphor" for the development of scientific theories. However, critical realists have failed to provide a detailed account of the part that metaphor plays in scientific theorizing. It is argued that such an account reveals that metaphor is integral to science, as understood by critical realists, serving both to provide suggestions of scientific models and a theoretical vocabulary in terms of which scientists can structure and so understand their subject matter. (Copyright 1996 by Taylor and Francis Group)