At the time of writing (mid-October 1998) we can look back at what has been a very successful ECOOP 98. Despite the time of the year in the middle of what is traditionally regarded as a holiday period ECOOP'98 was a record breaker in terms of number of participants. Over 700 persons found their way to the campus of the Brussels Free University to participate in a wide range of activities. This 3rd ECOOP workshop reader reports on many of these activities. It contains a careful selection of the input and a cautious summary of the outcome for the numerous discussions that happened during the workshops, demonstrations and posters. As such, this book serves as an excellent snapshot of the state of the art in the field of object oriented programming. About the diversity of the submissions A workshop reader is, by its very nature, quite diverse in the topics covered as well as in the form of its contributions. This reader is not an exception to this rule: as editors we have given the respective organizers much freedom in their choice of presentation because we feel form follows content. This explains the diversity in the types of reports as well as in their lay out."