Dirac's new relativistic wave equation and its generalization -- Unitary representations of the poincare group in the Thomas form: Quasi-Newtonian coordinates -- Explicitly poincare invariant formulation, relation to supersymmetry, no-go theorems -- Constrained Hamiltonean mechanics -- Vector Lagrangian model -- Lagrangian spinor model, electromagnetic interaction -- Further analysis of the classical motion of the spinor model.