  New insights into the combinatorial structure of the Mandelbrot set are given
by `Correspondence' and `Translation' Principles both conjectured and partially
proved by E. Lau and D. Schleicher. We provide complete proofs of these
principles and discuss results related to them.
  Note: The `Translation' and `Correspondence' Principles given earlier turned
out to be false in the general case. In April 1999, an errata was added to
discuss which parts of the two statements are incorrect and which parts remain
true.
