The Bottom Change predates the now more common Top Change. In it, the right hand places its card on the bottom of the deck as it retreats with the top card. The technique appeared in Henri Decremps's Testament de Jerome Sharp, 1786, p. 105. A multiple or packet Bottom Change appeared in Ellis Stanyon's Magic, Vol. 13 No. 3, Dec. 1912, p. 18.
The Bottop Change is often credited to Ed Marlo and is the name he applied to it (having been given the name by Bert Fenn). However, the technique predates him. It's essentially an inversion of the Bottom Change technique: the right hand places its card on top of the deck as it retreats with the bottom card. Clayton W. Rosencrance described this in The Sphinx, Vol. 35 No. 9, Nov. 1936, p. 240. Ed Marlo later reinvented it and published it in The Linking Ring, Vol. 30 No. 2, Apr. 1950, p. 87. He oddly touts the advantage of this technique being that it allows continuous changes, even though the original Bottom Change has the same feature.