The Mummy!: A Tale of the Twenty-Second Century

The full text and images of the second edition from 1828, Volume I are available at The Internet Archive.
The full text and images of the second edition from 1828, Volume II are available at The Internet Archive.
The full text and images of the second edition from 1828, Volume III are available at The Internet Archive.

Originally published anonymously in 1827, and then quickly reprinted in 1828 (Both editions in 3 volumes).
Published again in 1872 in a larger format and single volume.
There are 'hints' in Worldcat ({{OCLC|233789323}}) and elsewhere that a printing was planned in 1988 by the publisher Yankee Book Peddler with an ISBN of 0915431033, but Worldcat shows no copies and only a single reference to this ISBN can be found online easily.
The 1994 release is a significant abridgment of the original work, but is the most accessible printed copy in the English language.
There are further hints in Worldcat that there may be a German translation from and also a Vietnamese abridgment out there, but further research is needed to confirm these publications and their details.

Published in Octavo (8vo, 8mo) Size. (Which perhaps leads to this editions rarity, Though the 1994 U. Mich. edition indicates that Warne's 1872 edition was a small printing)
Entered from a variety of secondary sources. Worldcat and LOC have no copies of this edition, but it is well referenced elsewhere.
Size taken from Pg. 149 of the Dictionary of Biography.
Bleiler (The Early Years) Indicates that this edition had a "fine pictorial front cover", but the artist is unknown at this time.