Lyndon Hardy is an American fantasy author and physicist.
He is the creator of a loosely-linked fantasy series called Magic by the Numbers set in a world with five magical systems: Thaumaturgy (Sympathetic Magic), Alchemy (magic potions), Magic (creation of new Ancient Artifacts), Sorcery (Mind Manipulation), and Wizardry (Summoning Ritual). Each of the novels has a different protagonist. The first three were Master of the Five Magics (1980), Secret of the Sixth Magic (1984), and Riddle of the Seven Realms (1988). Modified forms of all there were issued in 2016. Since then he has written two further novels: The Archimage's Daughter (2017) and Magic Times Three (2020).