Divergence in Gestalt therapy?

Joe Wysong's comments in regards to Kepner's book _Body Process_ have triggered a number of thoughts for me. In reading various articles over the years, I have noted a dichotomy between various schools of Gestalth therapy and a tnednecy to dismiss the ideas and contributions of other schools. For example, the "New York" school seems to reject the writings of members of the "Cleveland School" in critiques and reviews of the latter's works, on the basis that those writings do not constitute "Gestalt therapy." Gestalt therapy seems to be restricted to the authors cited by Wysong: Perls, Hefferline & Goodman; the Polsters; Gary Yontef. My questions are "how is Gestalt therapy defined? How does it grow theoretically?" How do we avoid being in the situation of some psychoanalysis theorists who assert that Freud's works constitute the whole truth and everything else is inaccurate or heretical?

• Criterion for Gestalt Therapy by Joe Wysong, Editor, The Gestalt Journal, 3/11/97
• I'll Start With This... by Philip Brownell, 3/12/97
  • Could Use some Clarification by Ed Riemann, 3/12/97
    • Phenomenology and Dialogue by Philip Brownell, 3/13/97
• Condensing the Field by Philip Brownell, 3/15/97
  • Time by Joe Wysong, Editor, The Gestalt Journal, 3/15/97