This thesis describes the stand-alone discovery and measurement of the
Higgs boson in its decays to two W bosons using the Run-I ATLAS dataset.
This is the most precise measurement of gluon-fusion Higgs boson
production and is among the most significant results attained at the
LHC. The thesis provides an exceptionally clear exposition on a
complicated analysis performed by a large team of researchers. Aspects
of the analysis performed by the author are explained in detail; these
include new methods for evaluating uncertainties on the jet binning used
in the analysis and for estimating the background due to associated
production of a W boson and an off-shell photon. The thesis also
describes a measurement of the WW cross section, an essential background
to Higgs boson production. The primary motivation of the LHC was to
prove or disprove the existence of the Higgs boson. In 2012, CERN
announced this discovery and the resultant ATLAS publication contained
three decay channels: gg, ZZ, and WW.