  It is a basic question in contact geometry to classify all non-isotopic tight
contact structures on a given 3-manifold. If the manifold has a boundary, we
need also specify the dividing set on the boundary. In this paper, we answer
the classification question completely for the case of a solid torus by writing
down a closed formula for the number of non-isotopic tight contact structures
with any given dividing set on the boundary of the solid torus. Previously,
only a few special cases were known due to work by Honda.
