Why is a raven like a writing-desk? The concept of similarity lies at the heart of this new book on contrastive analysis. Similarity judgements depend partly on properties of the objects being compared, and partly on what the person judging considers to be relevant to the assessment; similarity thus has both objective and subjective aspects. The author shows how contrastive analysis and translation theory make use of the concept in different ways, and explains how it relates to the problematic notions of equivalence and tertium comparationis. The book then develops a meaning-based contrastive methodology, and outlines one theory of semantic structure which can be used in this methodology. The approach is illustrated with four sample studies covering different kinds of phenomena in some European languages. The final part of the book proposes an extension of the theoretical framework to cover contrastive rhetoric: the aim is to suggest a unified approach linking aspects of semantics, pragmatics and rhetoric. Keywords: similarity, contrastive analysis, functional grammar, semantics, rhetoric, translation.