This multiple shift using the plunger principle was published by Edward Marlo in The Cardician in 1953, p. 58. Marlo writes in the “Credits” section (p. 195) of this book: “If it weren't for the fact that Bert Fenn, Neal Elias and myself were busy trying to devise simpler, subtler, more deceptive ways of accomplishing Vernon's Multiple Shift (I believe Louis Zingone used the basic principle to control one card) I would never have devised the Simple Shift in Chapter Four.” Dai Vernon's Multiple Shift was published in Arthur Buckley's Card Control, 1946, p. 20. As would be expected of a derivative, Marlo's Simple Shift shares the same core mechanics as its parent, but it differs in a number of details.
In the same section of The Cardician (p. 194), Marlo mentions that Bert Fenn, in his private notes, dated his entry of Marlo's Simple Shift January 1949. It is reasonable to assume that this date is near that of the creation of Marlo's handling, since he, Fenn and Elias were exploring variations of the Vernon sleight together. Eight years later, Marlo wrote that he came up with his handling in 1946 (see his The Multiple Shift, 1961, p. 35), the year Vernon's shift was published. Marlo's memory may have been less precise at this time. The first ads for Buckley's Card Control in The Sphinx, The Linking Ring and The Conjurors' Magazine don't appear until the November 1946 issues, and an extract from the book appearing in that month's issue of The Sphinx (Vol. 45 No. 9, p. 265) proclaims “from the forthcoming Arthur Buckley Book 'Card Control.'” This suggests that the book didn't hit the shelves until late 1946, giving Marlo limited time for experimenting, although, given his enthusiasm, it is conceivable.
Another man had also been working on a variant of the multiple shift based on the Plunger Principle. Dominic Twose points out that, in the May 1953 issue of Hugard's Magic Monthly (Vol. 10 No. 12, p. 1084), Fred Braue published his “Ace Control”, which is in most major elements the same sleight as Marlo's Simple Shift. The major difference between Marlo's handling and Braue's is how the desired cards are controlled after being apparently pushed into the deck. Marlo used a key card to mark their location near the top. Braue caught a break when stripping out the injogged packet, and then did a Pass at the break, bringing one card of the required four to the top of the deck, and the other three to the bottom.
Braue's article appeared seven months before the release of Marlo's The Cardician, which was advertised in the November 1953 issue of The Linking Ring as “Ready Dec. 1—Just In Time For Christmas” (Vol. 33 No. 9, p. 9).
Complicating the matter further, Steve Reynolds points out a typewritten copy of the Braue article from Hugard's in a Sid Lorraine notebook devoted to Ace Tricks. This typescript copy of Braue's article has two added notations by Lorraine:
After the title “Ace Control”, “Ed Marlo” is inserted in parentheses; and at the end of the article Lorraine typed this note: “Told in confidence by Ed Marlo to someone who then passed it on to others on the West Coast. F.I.” Since Braue lived in the Oakland, California, area, the implication is clear. The initials “F. I.” seem to be those of Lorraine's source for this information; possibly Frances Ireland, a likely conduit for information between Chicago, where she and Marlo resided, and Toronto, Lorraine's home turf. The Ireland Magic Company was the publisher of The Cardician and other early Marlo works.
The innuendo directed at Braue seems uncharitable. No instance in his long writing career is known of him putting his name on another magician's idea; and since Vernon's Multiple Shift had been in print for seven years, independent invention inspired by this sleight is far more plausible.
The last entry of this Lorraine notebook describes the Vernon Multiple Shift, without attribution, but concludes with: “NOTE: See Art Buckley's 'Card Control,' for similar method of controlling four aces; also, method of Sam Horowitz in notes. (Shown to me by Ed Marlo in Chicago, Oct. 14, 1948).”
Lorraine seems to have noted differences in the handling shown him by Marlo and Vernon's handling in Card Control, but these aren't clear in his undetailed description of the sleight.
Also see Plunger Principle.