  A spherical two-distance set is a finite collection of unit vectors in
$\reals^n$ such that the set of distances between any two distinct vectors has
cardinality two. We use the semidefinite programming method to compute improved
estimates of the maximum size of spherical two-distance sets. Exact answers are
found for dimensions $n=23$ and $40\le n\le 93\; (n\ne 46,78)$ where previous
results gave divergent bounds.
