While this principle is generally credited to Charles Jordan due to its appearance as “Tracking the Dovetail Shuffle to Its Lair” in Thirty Card Mysteries, 1919, p. 7 of the second edition. However, Jordan was preceded by C. O. Williams in the use of a single shuffle to retain two sequences mixed together. Williams's idea was published in Stanyon's Magic, Vol. 13 No. 12, Sep. 1913, p. 100. Jordan, in his introduction to the above book (p. 1), acknowledges Williams's prior claim. Jordan had published this shuffle principle three years prior to Thirty Card Mysteries in Thayer's Magical Bulletin, Vol. 9 No. 7, Jul. 1916, np., apparently before becoming aware that it had been published in 1913 by Williams.