Introduction to the Special Issue The fifth International Workshop on Object-Orientation in Operating Systems (IWOOOS'96) was held October 1996 in Seattle, Washington, in conjunction with the Symposium on Operating Systems Design and Implementation (OSDI). The workshop went very well with a post workshop review showing that most attendees were extremely excited about future IWOOOS workshops. This year, the workshop format has changed from a few long and short papers to a larger set of short papers. The workshop contributed papers in new topics such as mobility, customization, adaptation, and system support for objects. Approximately 60 participants have attended IWOOOS. One of the most important aspects of a workshop is the conversations that take place during the workshop. In this special issue of TCOS, a digest of some of the most important discussions is presented. In addition, abstracts of most of the papers that appeared in the workshop proceedings are included. This digest was compiled with the help of J. Foxgord, M. Horie, J. Itoh, S. Khan, and J. Pang of he University of Victoria, Canada. Copies of the IWOOOS proceedings can be obtained directly from the IEEE CS press (184 pages. October 1996. Softcover. ISBN 0-8186-7692-2. Catalog # PR07692 $25.00 Members / $50.00 List). The IEEE CS Press can be reached by phone (+1-800-CS-BOOKS from the US, +1-714-821-8380, outside the US), by fax (+1-714-821-4641), or via e-mail (cs.books@computer.org). Nayeem Islam, Guest Editor and IWOOOS 96 Program Chair IBM TJ Watson Research Center P.O. Box 704, New York, NY 10598 Tel: (914) 784-7210 (office) nayeem@watson.ibm.com