CERN Accelerating science

The interplay between precise theory predictions and experimental measurements has written a success story in particle physics. After a brief journey into history we will review recent developments which have led  to "revolutions" with regard to precision calculations and to new insights into the structure of quantum field theory. The second part of the talk will focus on phenomenology, especially on Higgs boson pair production as a window to physics beyond the Standard Model, manifesting itself in a modification of those Higgs couplings which are still to a large extent unconstrained, in particular the Higgs boson self-coupling.