  A real semisimple Lie group G_0 embedded in its complexification G has only
finitely many orbits in any G-fag manifold Z = G/Q. The complex geometry of its
open orbits D (flag domains) is studied from the point of view of compact
complex submanifolds C (cycles) which arise as orbits of certain distinguished
subgroups. Normal bundles E of the cycles are analyzed in some detail. It is
shown that E is trivial if and only if D is holomorphically convex, in fact a
product of C and a Hermitian symmetric space, and otherwise D is pseudoconcave.
