Do As I Do
Do As I Do is a classic plot in card magic where a spectator, with his own deck of cards, copies the movements of a magician resulting in both of them ending up selecting the same card.
Note: Not to be confused with Do as I Do, You Can't or Vernon's Variant from Ultimate Secrets of Card Magic in which a spectator tries to follow along with the magician, but fails.
The premise of this trick can be found in Robert-Houdin's The Sympathetic Cards in The Secrets of Conjuring and Magic (1868 in France & 1878 in England as translated by Prof. Hoffmann). Two spectators choose a card but not the magician.
Roterberg provided 3 methods in New Era Card Tricks (1897).
In 1910, the title "Do As I Do" appears in Ten Self-working Master Card Effects with Ordinary Playing Cards by Sydney Lawrence.
William Goldman used the trick as a plot device (as well as explain it) in his novel Magic (1976).