The purpose of the series is to present collections of specific studies on particular topics in a format that facilitates cross-linguistic and cross-theoretical comparison. Each handbook takes up a single theme and includes a questionnaire; both the individual studies and the summary paper synthesizing the results of the comparison reflect the structure of the questionnaire. Unlike other handbooks that consist of chapters organized by theoretical topics, the handbooks of this series present empirical studies on various languages uniformly structured to facilitate comparison. A typical volume examines a grammatical feature or construction across languages (such as interrogative structures or numeral constructions), offers a survey of that feature through in-depth analyses cast in roughly the same theoretical framework, and formulates cross-linguistic generalizations. The handbooks also include accounts of constructions cast in different theoretical frameworks so that the empirical differences among the theories can be assessed and their similarities revealed. The volumes are accessible to the general academic community of linguists, meet the needs of students on the undergraduate and graduate level, and are of interest to specialists as well. Each volume is self-contained. Some of the volumes have associated websites to provide additional materials.