On the Spinor Equations for Particles with Arbitrary Spin and Rest Mass Zero

The spinor equations for arbitrary spin and rest mass zero are examined in some detail. Fierz has shown that for all values of the spin f(>1/2) there exists only two "really" independent plane wave solutions instead of ($2f+1$) when the rest mass is not zero. Fierz later showed, in rather a complicated way, that these two plane waves correspond to components of spin ±f along the momentum vector of the wave. We will arrive here at the same result but in a much simpler and more direct way.