A precursor to this idea was the Mirror Glass, credited to Hofzinser (Barton Whaley cites an 1872 creation date in The Encyclopedic Dictionary of Magic, 1989, p. 609).

Another related item is the “Transparent Egg Bag”, which employed a different method (a see-through mesh front with a black backing, and a secret compartment in the back panel concealed by the Black Art principle). This surfaced at least as early as 1923. A version was marketed by Conradi circa 1924 (see a mention of it in The Sphinx, Vol. 23 No. 5, July 1924, p. 158). The trick's invention was claimed by the Austrian manipulator, Larette; see The Linking Ring, Vol. 9 No. 7, Sep. 1929, p. 728.

Robert Harbin published what we now think of as a clear change bag, constructed from cellophane, under the title “Visible-Invisible Change Bag” in Abracadabra, Vol. 9, No. 227, June 3, 1950, p. 293. (It is worth mentioning that Harbin's version had a feature that is missing from almost all of the later reinventions.) Other than a brief favorable mention in Dariel Fitzkee's literary review column in Genii, Vol. 14 No. 12, Aug. 1950, p. 430, the Harbin bag seems to have gone unnoticed. The description from Abra was included in a later book compilation, Habincadabra, 2005, p. 133.

In The New Phoenix No. 319, Nov. 1954, p. 85, Jay Marshall writes that “Homer Hulse mentioned a transparent change bag he intends to market.” There does not appear to be any evidence that he ever did.

In March 1958, Tannen's began advertising “The Visible Prediction,” the clear change bag with no attribution. That same year, this was imported back to England by Harry Stanley, who added a routine using the prop by Maurice Fogel called “The Eternal Triangle”, which is presumably why Fogel is sometimes credited with having invented the item.

Perhaps the terse ad copy was too oblique, because the prop was still largely unknown when in The Linking Ring, Vol. 41 No. 1, Mar. 1961, p. 67, the “Transparent Changing Bag” was offered by Adolph H. Humphreys and praised as a useful new idea by Parade editor, Eddie Clever.

Circa 1960, U. F. Grant marketed a “Transparent Egg Bag” (credited to Jack Chanin) and a “Transparent Dove Bag”. During that decade, he also sold a “Transparent Change-Bag”. The earliest ad seems to be in Genii, Vol. 31 No. 2, Oct. 1966, p. 99. The ad is for Morcom's Enterprises, but the title and price of the prop ($3) make it almost surely Grant's. It is advertised by Grant in Genii, Vol. 31 No. 6, Feb. 1967, p. 237. Although it is usually referenced as having been released closer to 1960, this is probably due to a conflation of the prior “transparent” bags and this one.

At any rate, in modern times the credit, when it's given at all, is most often given to Grant, but the correct citation is clearly Robert Harbin.

(Above history researched by Max Maven)