John Nolte, The Philosophy, Theory and Methods of J.L. Moreno: The Man Who Tried to Be God (2014) New York, London, Routledge. Available in ebook formats as well as hard cover. Note: Chapter 8: "Sociometry, a New Model for Social Science" pages 129-154; and, Chapter 9: "Sociometric Theory" pages 155-178.|
Jonthan D. Moreno. Impromptu Man: J.L. Moreno and the Origins of Psychodrama, Encounter Culture and the Social Network. (2014) New York, Bellevue Literary Press. Available in soft cover and ebook formats.
Both of these books are well written, are engaging, and offer both historical perspectives and provide linkages to other major and minor contributors to the research and culture of the times.