A fictional character created by Robert A. Heinlein.
Full name: Elizabeth Andrew Jackson Libby Long
Andrew Jackson Libby is a descendent of Maureen Johnson, through her daughter Carol Long (see Santa Carolita). He was born in Arizona after the Second Revolution to a family which had converted to the New Crusade of Nehemiah Scudder. Because of this, he was a grown man before he found out that he was a member of the Howard Families.
In the meantime, Andrew Jackson Libby performed a stint in the Cosmic Construction Corps, where his ability to perform complex mathematical calculations at lightning speeds was discovered by his commanding officer, Captain Doyle. He then joined the Navy as a spaceman, where his connection to the Howard Families was rediscovered by one of his superior officers.
When the Howard families were forced to flee Earth on the commandeered starship New Frontiers, Libby developed a "star drive" which allowed the New Frontiers to tavel at faster-than-light velocities. It was during this exploit that Libby first met Lazarus Long. Libby would travel with Lazarus until his death, eventually becoming his most trusted companion. He had twenty-one children.
After Libby's death, Lazarus put Libby's body into space, intending to return later to transport Libby to his native land of Arizona. However, when Lazarus returned, Libby's body was missing. What had happened was that Libby's body was transported through several temporal shifts by several future versions of Lazarus.
The ultimate result of these shifts was that a clone of Libby was grown at the Howard Clinic on Tertius Tellus into which Libby's memories were placed; his original body was incinerated upon re-entry into Earth's atmosphere upon a trajectory that would have ended in Arizona.
Libby was found to be XXY, and was asked, both while conscious and while under hypnosis, if he prefered to be a man or woman. He answered woman, and it was as Elizabeth Andrew Jackson Libby Long that he joined the Long Family on Tertius.
Libby continues her research as a theoretical and applied mathematician, both as a consultant to the Howard Clinic and as part of the Time Corps, working with such mathematicians as Jacob Burroughs. At the time she first met Dr. Burroughs, she had had five children as a woman, although she has had several more since that time.
Andrew Jackson Libby appears in the short story "Misfit" and the novels Methuselah's Children, Time Enough for Love, The Number of the Beast, The Cat Who Walks Through Walls, and To Sail Beyond the Sunset.