Friday by Robert A. Heinlein 1

Friday is a secret courier. She is employed by a man known to her only as "Boss." Operating from and over a near-future Earth, where chaos is the happy norm, she finds herself on assignment at Boss's seemingly whimsical behest. From New Zealand to Canada, from one to another of the new states of America's disunion, she keeps her balance nimbly with quick, expeditious solutions to one calamity and scrape after another. "FRIDAY IS A SUPERBEING. . . . Engineered from the finest genes, and trained to be a secret courier in a future world of chaotic ferocity and intrigue, she can think better and make love better than any of the normal people around her."