It is propitious that the 25th year of publication of the International Journal of Fracture should coincide with the opportunity to support the recognition by the Society of Engineer­ ing Science of the 65th birthday of the Founding Editor-in-Chief, Professor M.L. Williams. At its 24th Annual Meeting at the University of Utah in September 1987, the Organizing Committee of the Society chose to honor Professor Williams by reserving several sessions for contributions from his colleagues working in the mechanics of fracture and associated mechanical property-structure relationships. We are therefore pleased to welcome Professor E.S. Folias, Professor of Mechanical Engineering, University of Utah, and a member of the Editorial Committee as the Guest Editor for the first three issues of Volume 39 of the Journal. We have also noted that the University of Utah was one of the three homes for the Journal, sandwiched between the original home at the California Institute of Technology in 1965 and its current location at the University of Pittsburgh. In observing these dual anniversaries, the publishers not only enthusiastically support the presentation of these special papers, but also wish to extend to Professor Williams our own best wishes on his personal anniversary, and to thank him and all the authors, reviewers, and particularly M.e. Williams, J.L. Swedlow and the Regional Editors for their respective contributions as we observe this 25th milestone.