John Ellis
These lecture notes review the theoretical background to the Higgs boson, provide an introduction to its phenomenology, and describe the experimental tests that lead us to think that "beyond any reasonable doubt, it is a Higgs boson". Motivations for expecting new physics beyond the Standard Model are recalled, and the Standard Model effective field theory is advocated as a tool to help search for it. The phenomenology of N=1 and N=2 supersymmetric Higgs bosons is reviewed, and the prospects for possible future Higgs factories are previewed.