The papers in this volume were selected for presentation at the Fourth Annual International Computing and Combinatorics Conference (COCOON’98), held on August 12–14, 1998, in Taipei. The topics cover most aspects of theoretical computer science and combinatorics related to computing. Submissions to the conference this year was only conducted electronically. Thanks to the excellent software developed by the system team of the Institute of Information Science, we were able to make virtually all communications through the World Wide Web. A total of 69 papers was submitted in time to be considered, of which 36 papers were accepted for presentation at the conference. In addition to these contributed papers, the conference also included four invited presentations by Christo Papadimitriou, Michael Fishcher, Fan Chung Graham and Rao Kosaraju. It is expected that most of the accepted papers will appear in a more complete form in scientific journals. Moreover, selected papers will appear in a special issue of Theoretical Computer Science. We thank all program committee members, their support sta? and referees for excellent work within demanding time constraints. We thank all authors who submitted papers for consideration. We are especially grateful to our colleagues who worked hard and offered widely difiering talents to make the conference both possible and enjoyable. August 1998 Wen-Lian Hsu and Ming-Yang Kao Program Co-chairs COCOON’98 Organization COCOON’98 is organized by the Institute of Information Science, Academia Sinica, Taipei, Taiwan, ROC and in cooperation with Institute of Information and Computing Machinery (IICM), Taiwan, ROC.