Gelbmann's book "Observations on Transaction. A Discussion of Watzlawick's Second Axiom" (Frankfurt 2002) deals with two aspects of interpersonal communication - the content aspect and the relationship aspect. It criticizes approaches towards a philosophy of communication which start from notions like ordinary language or language instinct or communication as oriented toward (mutual) understanding. Alternatively, it proposes an attempt to base a conception of communication on the constructivist's understanding of the term of observation.
For more information go to Gerhard's own site.
Gerhard Gelbmann is Visiting Scholar at WAB.