The informal papers reproduced here represent theory sessions of use at various NTL Institute Laboratories. They are intended as supplemental notes helpful in understanding various laboratory experiences. The ideas and concepts touched on here have proved useful in laboratories over the years, and they will be relevant to much that happens at a laboratory session.
It is impossible to designate authorship for some of these articles : the concepts have been reused and, in some cases, altered and refined over the years in various training programs. Authorship is indicated wherever it is known. Some editing or rewriting of articles from the previous edition has been done by the current editors whose names are given below.
The Appendix to this reader provides information about the activitiesof the NTL Institute and both general and specialized bibliographies. Cyril R. Mill, Ph.D. Lawrence C. Porter, Ed.D. Program Director Program Manager Center for Systems Change Center for Professional Development NTL Institute.