  A remarkable theorem due to Peter Dembowski states that if $I$ is an
inversive plane of even order $q$ then $q$ must be a power of two and $I$ must
be the incidence system of points versus plane ovals in an ovoid in the
projective $3$-space over the field of order $q$. In this paper we present a
short and self-contained proof of this result. Our proof depends on the
classification due to Benson of the symmetric and regular finite generalized
quadrangles. Included here is a deduction of Benson's Theorem from the
Dembowski-Wagner combinatorial characterization of finite projective
geometries.
