To establish the Higgs mechanism sui generis experimentally, the
self-energy potential of the Higgs field must be reconstructed. This
task requires the measurement of the trilinear and quadrilinear
self-couplings, as predicted, for instance, in the Standard Model or
in supersymmetric theories. The couplings can be probed in multiple
Higgs production at high-luminosity e+e- linear
colliders. Complementing earlier studies to develop a coherent picture
of the trilinear couplings, we have analyzed the production of pairs
of neutral Higgs bosons in all relevant channels of double
Higgs-strahlung, associated multiple Higgs production and WW/ZZ fusion
to Higgs pairs.