ABSTRACT
These special issues were organized by the three of us in honor of Allan Hoffman's 70th birthday, as explained in the Foreword. In the Preface, Buddy Ratner has given a concise and broad overview of the public aspects of Allan Hoffman's career that help to explain the overall impact of his work. As Buddy has described, these contributions can be associated with his creativity and quality research, effectively communicated through his many publications and presentations around the world.
