Every card is on the table, use four free cells to unpack the columns and build each suit up to king.
All cards are dealt face-up into eight columns. Build down in alternating colors within the tableau, and use the four free cells as single-card parking spots to maneuver. Move cards to the four foundations in ascending order by suit, from ace to king. Because nothing is hidden, nearly every deal can be solved with careful planning.
FreeCell has a precise author and a precise machine. Its immediate parent is Baker's Game, described by Martin Gardner in his Mathematical Games column in Scientific American in June 1968 — a game C. L. Baker had learned from his father, who had it from an Englishman in the 1920s.
Baker's Game built the tableau by suit. Paul Alfille changed one rule, building by alternating colours instead, and in doing so turned a near-unwinnable curiosity into a game where almost every deal can be solved. He wrote the first computer version as a medical student at the University of Illinois, in TUTOR on the PLATO system.
Older ancestors are proposed — Eight Off, and a Scandinavian game called Napoleon in St. Helena dating to 1945 — but the version the world plays is Alfille's, and it reached that world because Microsoft shipped it.
FreeCell is the open-information patience game where skill, not luck, wins the deal. Free to play in your browser with a daily and unlimited practice, made in-house at PlayPendium.