  Methods of spinor calculus in particle physics are described in this series
of four chapters written in french. A special emphasis is made on the
well-known helicity-coupling scheme which is the guiding thread of all these
methods. Numerous explicit formulas are given for projectors onto two-particles
helicity states as well as for bilinears of Dirac spinors, for the s and t
channels of a given two-body process involving spin 1/2 particles. In the last
chapter, applications to various elementary processes are given.
