Foster, Alan Dean. "Polonaise"
Divergence: c 1772 CE
What if: Poland became an important player on the world stage, capable of putting down Hitler in six months.
Summary: A secret Polish space project to impose world peace in an age of nuclear proliferation.
Published: In Beyond Time (ed. Sandra Ley), q.v.; and With Friends Like These…, Ballantine 1977 (0345257014).