  For a smooth manifold $N$ denote by $E^m(N)$ the set of smooth isotopy
classes of smooth embeddings $N\to\mathbb R^m$. A description of the set
$E^m(S^p\times S^q)$ was known only for $p=q=0$ or for $p=0$, $m\ne q+2$ or for
$2m\ge 2(p+q)+\max\{p,q\}+4$. (The description was given in terms of homotopy
groups of spheres and of Stiefel manifolds.) For $m\ge2p+q+3$ we introduce an
abelian group structure on $E^m(S^p\times S^q)$ and describe this group `up to
an extension problem'. This result has corollaries which, under stronger
dimension restrictions, more explicitly describe $E^m(S^p\times S^q)$. The
proof is based on relations between sets $E^m(N)$ for different $N$ and $m$, in
particular, on a recent exact sequence of M. Skopenkov.
