This publication contains the proceedings of the 4th International Conference on Object-Oriented Information Systems. The first three OOIS conferences were held in London UK (1994), Dublin Ireland (1995) and again in London in 1996. In response to the Call for Papers we received 91 submissions which were reviewed by members of the Program Committee. Each paper was refereed by at least three reviewers, and following discussion with PC members, 40 of the papers were accepted for presentation at the conference, and for publication in this volume. In addition to the contributions from authors,...