The Unshuffled plot generally features writing on the edge of a deck that keeps changing with each shuffle until it says “Unshuffled”, and the pack is found back in new-deck order. For a kicker, the writing then changes into the name of a previously selected card. There are several principles in play.
Writing on the side of a deck as a means of sending secret messages is mentioned in Giovanni Battista Della Porta's De furtivis literarum notis, vulgo de ziferis, 1563, p. 345 of the 1658 English translation, London: Thomas Young and Samuel Speed.
The first to apply the idea to a magic trick was Hen Fetsch, in The Linking Ring, Vol. 27 No. 12, Feb. 1948, p. 50, under the title “Mixed Magic”. Winston Freer also used the idea for his “Half-wit Deck,” 1961, with patter by Gene Gordon (who marketed it).
The idea of using the same shuffle several times to return the cards to their original order appeared in W. Hooper's Rational Recreations Volume One, 1774, p. 78. Hooper describes various uses for the concept, one of which is to write several letters on each card. After the first shuffle, the first letters of each card spell out a message; after the second shuffle, the second letters on each card spell out a new message. With each new shuffle a further message is revealed.
The combination of concepts really took off in the 1970s. Steve Spillman introduced the idea of causing the writing to change into the name of a selection in My Hands Can Be Yours, 1973, p. 38. Earl Keyser utilized the faro shuffle in conjunction with edge writing in his “Mirage Deck”, in Epilogue, No. 16, Nov. 1972 (sic), p. 152. Karl Fulves, in introducing the Keyser article, says he received it from Keyser in Sep. 1970, and failed to get it into print for three and a half years. It follows that the Nov. 1972 date was not the actual date of publication; Fulves's publishing schedule for his periodicals frequently ran late during this period. In Epilogue, No. 21, dated July 1974, p. 202, Fulves repeats Keyser's right to the idea, in response to a similar construct appearing in Genii “a month or so before Epilogue #16 appeared.” This would seem to refer to Dr. Michael S. Ewer's influential article in Genii, Vol. 37 No. 11, Nov. 1973, p. 465. In response to Ewer's article, Bob Wicks followed with “The Handwriting on the Deck” in Genii, Vol. 38 No. 8, Aug. 1974, p. 330. Wicks suggested the idea (among several) of using the word “unshuffled”. He added further ideas in “Reshuffling Unshuffled” in Fork Full of Appetizers, Book 2, 1984, p. 91, edited by Bill Miesel.
Paul Gertner published his popular—and now standard—version of the plot in Harry Lorayne's Best of Friends, 1982, p. 343. An updated version appeared in Gertner's Steel & Silver by Richard Kaufman, 1994, p. 143.
Stephen Tucker soon followed Gertner with his handling that allows for genuine shuffles before and during the trick. This is accomplished by having writing on only twenty-six cards, leaving the other twenty-six to be freely displayed and mixed. By giving the deck a single faro, the writing will expand through the deck and appear to fill the full edge of the pack. This appeared as “Edge Hog II” in Tucker's Cardiac Stimulation, 1984, p. 18. The next item in the book is “Edge Hog III” (p. 20), which has writing on only thirteen cards, allowing a full three-quarters of the deck to be genuinely shuffled before two faros cause the writing to appear.