The concept of a bottom slip cut dates back to the early 18th century. It appears in an Italian manuscript known as the Asti Manuscript, c. 1700, p. 63 of the Pieper translation. This manuscript was translated in Gibecière, Winter 2013, p. 29-234.
The 20th century kicked the idea into gear, starting with “The Mystery of the Aces” by Charles Jordan in Four Full Hands of Down to the Minute Magical Effects, 1922, p. 5 of the 1947 edition, and later in The Tarbell Course in Magic, Vol. 1, 1941, p. 261.
An application of the bottom slip cut, unfortunately without handling details, was treated by Stanley Collins as common knowledge in Gems of Personal Prestigitation, 1952, p. 9 (not published until Stanley Collins: Conjurer, Collector, and Iconoclast, 2003, by Edwin A. Dawes). Harry Lorayne's commonly used HaLo cut appeared in Rim Shots, 1973, p. 131. Richard Kaufman lays credit for Lorayne's breakless handling at Derek Dingle's door; see Genii, Vol. 67 No. 5, May 2004, p. 72.