The GNU Scientific Library (GSL) is a free numerical library for C and C++ programmers. This reference manual is the definitive guide to the library.

This book developed out of the twentieth anniversary conference of the Group for the Study of Irish Historic Settlement held in Dublin in 1989, at which it was decided that the papers should also be published. I would like to thank all the contributors for both their perseverance and their patience which has meant that this book has finally come to see the light of day. I would like to thank especially Dr Ruth Johnson, Curator of DVBLINIA, without whom this book would not have been produced. She spent many hours editing the contributions and she also produced the very successful bibliography which you will find at the end of the volume. Professor Anngret Simms was also very helpful both in reading the draft copy of the book and in the whole editing process. I would also like to thank the library staff in the Royal Irish Academy and Trinity College Dublin, for alltheir assistance. The staff of Routledge, Taylor and Francis Books Ltd are also owed a debt of de ep gratitude by the editor and authors for their efficiency and support in ensuring that this book saw the light of day: especially Victoria Peters, the Archaeology Editor, her Assistant Editor, Nadia Jacobson; and Barbara Duke, Senior Production Editor. Finally, I must also thank the external copy editor, Sophie Richmond, for all her extremely useful observations and corrections. Financialsupport has come from the Department of Medieval History, Trinity College Dublin, the Group for the S tudy of Irish Historic Settlement the Institute of Irish Studies, Queen’s University, Belfast and from the School of Irish Studies, Dublin, for which I am very grateful.