  Let $\Lambda$ be a finite-dimensional basic algebra over an algebraically
closed field $k$. The well-known Drozd's theorem asserts, that $\Lambda$ is
either tame or wild. The Crawley-Boevey's Theorem states that for a given tame
algebra $\Lambda$, and for each dimension $d$ almost all isomorphism classes of
indecomposable $\Lambda$-modules of dimension $d$ are isomorphic to their
Auslander-Reiten translations and hence belong to homogeneous tubes. In this
paper we prove the converse of Crawley-Boevey's Theorem and thus give an
internal description of tameness in terms of AR-quivers. This gives a complete
answer to a question posed by Ringel in \cite{R1}.
