"This volume presents the collective work of a team of twenty-one scholars that have investigated headless relative clauses in fifteen languages from five language families-all Mesoamerican but one. Headless relative clauses have received little attention in the linguistic literature, despite the many morpho-syntactic and semantic puzzles they raise within and across languages and for our understanding of human language in general. Headless relative clauses have been even more neglected in the study of Mesoamerican languages. This volume constitutes the first in-depth, systematic study of Headless Relative Clauses for any Mesoamerican languages we know of and the broadest and most articulated crosslinguistic study of headless relative clauses that has been conducted so far. For most of the languages in this volume, there is no descriptive or documentary material on wh-constructions in general, let alone headless relative clauses. Many of the languages are threatened or endangered; all are understudied. All of the chapters constitute original contributions to typological and theoretical linguistics. The first chapter introduces and defines the varieties of headless relative clauses that are investigated in the other chapters, compares them to two related and better-known constructions, namely headed relative clauses and wh- interrogative clauses, summarizes the main findings in a comparative prospective, highlights the importance of studying headless relative clauses to understand human language, and provides a methodological framework for the other chapters and future work. All the other chapters are language-specific and follow a uniform format to facilitate comparisons and generalizations across languages"--