It is a pleasure to present this volume consisting of a selection of papers presented at the 4th International Drying Symposium (IDS) held in Kyoto, July 9-12, 1984, under the sponsorship of the Society of Chemi cal Engineers, Japan. This book includes full texts of the ten keynote lectures and several papers which were presented in the technical sessions in the 4th IDS. As editors we had the arduous and unpleasant task of selecting papers for this volume. We were delighted with the high quality manuscripts sub mitted. We are grateful to the authors for their efforts in meeting the manuscript guidelines and also the deadlines. Aside from quality, we have attempted to maintain in this volume a balance of coverage in terms of topics as well as geography. Space restrictions prevented us from presenting all the high quality papers for publication in DRYING 85. Numerous papers of archival interest have been released for general publication in international journals. Several will no doubt appear in Drying Technology - An International Journal. Many others will find their way into other standard engineering journals as well. Over 120 papers from 30 countries were included in the Proceedings volumes distributed to all registrants in Kyoto. Numerous individuals, professional societies and organizations have contributed, directly or indirectly, to the success of the 4th IDS and hence to DRYING 85 as well. We wish to acknowledge in particular the monumental efforts of the Secretary of the 4th IDS, Professor M. Okazaki.