Description: Comedy in which a professor travels back in time to kill someone by killing their grandparent, but the results confound him. Explores many time travel scenarios in a short story format. When mad scientist Henry Hassel discovers his wife in the midst of committing adultery, he decides that simple murder would be intellectually unsatisfying; he therefore builds a time machine with the intention of killing his wife's grandparents in their youth, so that she will never have existed. When he returns to the present, however, nothing has changed. In a desperate attempt to alter history, Hassel begins killing historical figures of greater and greater significance (eventually including Mohammed, thus the story's title), only to learn that the nature of time is very different from what he had thought