Design Patterns: Elements of Reusable Object - Oriented Software (Old Edition) About the Author About the Author: The authors of Design Patterns: Elements of Reusable Object-Oriented Software, are Dr. Erich Gamma, Ralph Johnson, Richard Helm and John Vlissides. Dr. Erich Gamma is currently the technical director at the Software Technology Center of Object Technology International, Zurich, Switzerland. Dr. Ralph Johnson is part of the faculty at the University of Illinois, which is at Urbana-Champaign's Computer Science Department. Dr. Richard Helm is a member of the Object Technology Practice Group, IBM Consulting Group, Sydney, Australia. John Vlissides is a member of IBM T. J. Watson Research Center's research staff, in Hawthorne, New York. This team of authors is referred to as the gang of four.