Schroedinger-like formalism of relativistic quantum theory for spin-zero particles

This paper presents a Schroedinger-like formalism of relativistic quantum theory alternative to the Klein-Gordon theory for spin-0 particles. The Schrodinger-like wave equation thus obtained is form-invariant, though its form is not manifestly Lorentz-covariant in the conventional sense. The alternative formalism resolves the great difficulties of negative probability density and Zitterbewegung in the Klein-Gordon theory. Ehrenfest's theorem is preserved in the alternative formalism