  We deduce continuity and (global) wave-front properties of classes of Fourier
multipliers, pseudo-differential, and Fourier integral operators when acting on
Orlicz spaces, or more generally, on Orlicz-Sobolev type spaces. In particular,
we extend H{\"o}rmander's improvement of Mihlin's Fourier multiplier theorem to
the framework of Orlicz spaces. We also show how Young functions $\Phi$ of the
Orlicz spaces are linked to properties of certain Lebesgue exponents $p_\Phi$
and $q_\Phi$ emerged from $\Phi$.
