  These lectures give a pedagogical discussion of the computation of QCD tree
amplitudes for collider physics. The topics reviewed are: spinor products,
color ordering, MHV amplitudes, and the Britto-Cachazo-Feng-Witten recursion
formula. The lectures were presented at the XIII Mexican School of Particles
and Fields, 2008, and at the LHC Physics Summer School at Tsinghua University,
2010.
