A work- and learning-capable group does not develop on its own; it requires group leadership that must possess specific knowledge and skills. A significant support is provided by Theme-Centered Interaction (TZI), a concept aimed at social learning and personal development in group work. Angelika and Eike Rubner convey fundamental knowledge about what characterizes plurality in general and a group in particular, which conscious and unconscious processes are at play, and what development potential a capable group leadership can unfold. The development and methodology of TZI are precisely outlined in this book, complemented by a detailed presentation of the six-phase model developed by Angelika and Eike Rubner. Through concrete examples from practice, they describe not only the diversity.