Dr. Prein was for 34 years an Associate Professor for Conflict Management, Mediation, Intervention, and Group Facilitation at the Department of Social and Organization Psychology at Utrecht University in the Netherlands. His lifelong research interest has been the effectiveness of third party conflict intervention strategies and the intervention competencies of mediators. He combines in his work the perspectives and methods of social psychology and communication.

By order of The Netherlands Mediation Institute (NMI), he developed an instrument to measure the competencies of a mediator that is now being used in the official certification procedure for mediators in the Netherlands. He also has the task of educating and supervising other assessors.

He is one of the editors of the Handboek Mediation (Handbook of Mediation). This book forms, together with two other books (including his book Mediation in Praktijk) the official ‘body of knowledge’ for all mediators in the Netherlands (test items for the knowledge test for registration as a mediator are based on these three publications).

The last few years he has focused his research and writing on the mediation process. He published several books, book chapters and articles about conflict management and mediation. He served several years on the editorial board of the Journal Tijdschrift Conflicthantering; and he continues to serve on the editorial board of the Mediation Series (Mediationreeks), a series of books about mediation, as well as the editorial board of the official Handbook of mediation for the Netherlands. He also continues to work as a mediator, coach, trainer, and assessor. He developed and has given sindce 1998 with two collegues the basic mediation training for the section mediation of the Dutch Psychological Association (NIP) and is giving several other trainings on mediation and intervention techniques.