From Works of Wonder:
My favorite scene in the book, save the ending, was the handshake… Reading the manuscript, I was struck by the understated beauty of that scene and became determined to use it for the cover art. Again Giskard is pivotal, so he stands right of center, with the center point of the circular window*the future being his "heart," or where his heart would be were he human. The planet's fate hangs over him like a Damoclean sword. In the end, he must decide the fate of Earth's millions of souls, and later he passes this task on to the robot Daneel. For me, this handshake symbolizes the transference of duty from one robot to the other.