This volume consists of a number of detailed case studies of transitivity across a selection of languages – from North, Central and South America, New Guinea, Australia, the China/Myanmar (Burma) border, North-east Africa and the Caucasus. In the introduction we summarize the theoretical presuppositions and parameters, suggest generalizations that can be made on the basis of comparison of the individual studies, and draw attention to useful directions for further research.

§1 describes varieties of predicate arguments and clause types. §2 deals with classes of verbs, and transitivity-encoding devices. Then §3 presents an overview of derivations which change valency. In §4 we discuss derivations which typically reduce valency – passive, antipassive, reflexive, reciprocal and anticausative (plus the ubiquitous middle). §5 considers derivations which typically increase valency – applicative and causative (there is a full discussion of causatives in chapter 2). In §6 we emphasize the need for a holistic approach; every derivational process is likely to have syntactic, semantic and discourse/pragmatic aspects, each of which interrelates with and helps explain the others. §7 briefly discusses the propensities of different groups of verbs – according to their semantics – for taking part in the various derivations that affect valency. In §8 we look briefly at syntactic alternatives to valency-changing derivations; in some languages there may simply be alternative construction types, with no derivational link. §9 gives a short preview of each of the following chapters. Finally, in §10 we suggest a number of fruitful lines for further research.