The flight of the horse - Larry Niven

We don't know where on Earth you'll wind up,' Ra Chen had told him.

And the Director of the Institute for Temporal Research didn't know precisely when, either. All he knew was that Hanville Svetz would be travelling back in time almost 2,000 years.

But when he comes back, Hanville Svetz won't be alone. If his mission is successful he will be accompanied by a creature long extinct - a spectacular birthday present for the Secretary-General. His only help is a picture from a child's picture book. A picture of a horse.

And so begins the first incredible adventure in time of Hanville Svetz.