©Cedwir pob hawl. Ni cheir atgynhyrchu unrhyw ran o'r cyhoeddiad hwn, na'i gadw mewn cyfundrefn adferadwy, na'i drosglwyddo mewn unrhyw ddull na thrwy unrhyw gyfrwng, electronaidd, mecanyddol, llungopio, recordio, nac fel arall, heb ganiatâd ymlaen llaw gan y Cyhoeddwyr, Canolfan y Llyfr Aberystwyth Centre for the Book, 1999. ©All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, including photocopying and recording, nor stored in a retrieval system of any nature, without the written permission of the Publishers, Canolfan y Llyfr Aberystwyth Centre for the Book, 1999. Dymunir cydnabod cymorth ariannol o Gronfa Syr David Hughes-Parry, Prifysgol Cymru Aberystwyth, tuag at gyhoeddi'r gyfrol hon. Financial assistance from the Sir David Hughes-Parry Fund, University of Wales Aberystwyth, towards the cost of publishing this volume is gratefully acknowledged. Bwrdd Golygyddol Editorial Board: Andrew M W Green Hywel Roberts Gwerfyl Pierce Jones Rhidian Griffiths Dylid anfon erthyglau a deunydd arall i'w hystyried at: Yr Athro Hywel Roberts, Adran Astudiaethau Gwybodaeth a Llyfrgellyddiaeth, Prifysgol Cymru Aberystwyth, Llanbadarn Fawr, Aberystwyth SY23 3AS. Articles and other material should be sent for consideration to: Professor Hywel Roberts, Department of Information and Library Studies, University of Wales Aberystwyth, Llanbadarn Fawr, Aberystwyth SY23 3AS. Argraffiad Cyntaf /First Edition 1999 ISBN 1 86225 013 8 ISSN 1368 5902 Dyluniwyd gan Gyngor Llyfrau Cymru Designed by the Welsh Books Council Lluniau: Llyfrgell Genedlaethol Cymru Illustrations: National Library of Wales Cynhyrchwyd ac argraffwyd gan Lyfrgell Genedlaethol Cymru Produced and printed by the National Library of Wales.