  We describe the primitive central idempotents of the group algebra over a
number field of finite monomial groups. We give also a description of the
Wedderburn decomposition of the group algebra over a number field for finite
strongly monomial groups. Further, for this class of group algebras, we
describe when the number of simple components agrees with the number of simple
components of the rational group algebra. Finally, we give a formula for the
rank of the central units of the group ring over the ring of integers of a
number field for a strongly monomial group.
