  A universal description of particles with spins j greater or equal one ,
transforming in (j,0)+(0,j), is developed by means of representation specific
second order differential wave equations without auxiliary conditions and in
covariant bases such as Lorentz tensors for bosons, Lorentz-tensors with Dirac
spinor components for fermions, or, within the basis of the more fundamental
Weyl-Van-der-Waerden sl(2,C) spinor-tensors. At the root of the method, which
is free from the pathologies suffered by the traditional approaches, are
projectors constructed from the Casimir invariants of the spin-Lorentz group,
and the group of translations in the Minkowski space time.
