Forever by Robert Sheckley

With so much at stake, Charles Dennison should not have been careless. An inventor cannot afford carelessness, particularly when his invention is extremely valuable and obviously patentable. There are too many grasping hands ready to seize what belongs to someone else, too many men who feast upon the creativity of the innocent.

A touch of paranoia would have served Dennison well; but he was lacking in that vital characteristic of inventors. And he didn’t even realize the full extent of his carelessness until a bullet, fired from a silenced weapon, chipped a granite wall not three inches from his head.

Then he knew. But by then it was too late.

Charles Dennison had been left a more than adequate income by his father. He had gone to Harvard, served a hitch in the Navy, then continued his education at M.I.T. Since the age of thirty-two, he had been engaged in private research, working in his own small laboratory in Riverdale, New York. Plant biology was his field. He published several noteworthy papers, and sold a new insecticide to a development corporation. The royalties helped him to expand his facilities.

Dennison enjoyed working alone. It suited his temperament, which was austere but not unfriendly. Two or three times a year, he would come to New York, see some plays and movies, and do a little serious drinking. He would then return gratefully to his seclusion. He was a bachelor and seemed destined to remain that way.

Not long after his fortieth birthday, Dennison stumbled across an intriguing clue which led him into a different branch of biology. He pursued his clue, developed it, extended it slowly into a hypothesis. After three more years, a lucky accident put the final proofs into his hands.