  The present work draws on the understanding how notions of general potential
theory - as set up, e.g., by Fuglede - explain existence and some basic results
on the "magical" rendezvous numbers. We aim at a fairly general description of
rendezvous numbers in a metric space by using systematically the potential
theoretic approach. In particular, we generalize and explain results on
invariant measures, hypermetric spaces and maximal energy measures, when
showing how more general proofs can be found to them.
