The dynamics of the early universe may have been profoundly influenced
by spatial anisotropies. A search for such backgrounds in the context
of string cosmology has uncovered the existence of an entire class of
4D spatially homogeneous but not necessarily isotropic spacetimes, an
alogous to the class of Bianchi-type models in general relativity. Lea
ding-order solutions with vanishing cosmological constant but with non
-vanishing dilaton and antisymmetric field are explicitly found for al
l types. This is a new class of solutions, whose isotropy limits repro
duce all known and, further, all possible FRW-type of models in the st
ring effective-action context considered. There is always an initial s
ingularity and no inflation, Other features of the general solutions,
including their behavior under abelian T duality are also discussed.