  I present a concise review of the major issues and challenges in particle
physics at the start of the LHC era. After a brief overview of the Standard
Model and of QCD, I will focus on the electroweak symmetry breaking problem
which plays a central role in particle physics today. The Higgs sector of the
minimal Standard Model is so far just a mere conjecture that needs to be
verified or discarded by the LHC. Probably the reality is more complicated. I
will summarize the motivation for new physics that should accompany or even
replace the Higgs discovery and a number of its possible forms that could be
revealed by the LHC.
