This book took much longer to write than originally intended, particularly because very little was known about some of the regions to be covered, while much new material has become available these last few years. We hope this survey will in its turn inspire new research in the years to come.

We wish to thank first of all Bernard Comrie for his precise and encouraging comments on earlier chapter drafts. We are very grateful to Ana Fernández, Timothy Curnow, Knut Olawsky and Nicholas Ostler for reading and commenting on specific chapters of the book. A special word of thanks goes to Rodolfo Cerrón-Palomino for providing us with data from his ongoing research on the Chipaya language, and to Alfredo Torero for permitting us to use his unpublished work on Puquina. Many colleagues and friends have contributed over the years with valuable advice and commentary, by providing us with newly published or little-known publications, or by calling our attention to new materials and research results. Their generosity is duly remembered, although space does not allow us to mention each of them individually.

Our gratitude extends in particular to those academic institutions that have provided the environment and the facilities necessary for an undertaking such as the present one: the Netherlands Institute of Advanced Studies (NIAS) in Wassenaar, the Netherlands, the Research Centre for Linguistic Typology (RCLT) at La Trobe University in Victoria, Australia, the Research School CNWS of Asian, African and Amerindian Studies and the Faculty of Letters of Leiden University.