  In this talk I give an introduction to methods used to give a model
independent description of QCD effects in B-decays. I discuss three useful
expansions: mb/mW << 1 for the electroweak Hamiltonian, LambdaQCD/mb << 1 for
Heavy Quark Effective theory, and LambdaQCD/Q << 1 for the Soft-Collinear
Effective Theory where Q ~ mb is the large energy of light final state hadrons.
I discuss predictions that can be made with each expansion.
