The Gustave Dore illustrated books of Series 78 are among the most desired and collected of all Altemus books. Certainly they are not the scarcest but the large Dore illustrations drive the desirability. The volumes were published between 1889 and 1903. It is not unusual for these books to sell in the hundreds of dollars.
There are six books in the series not including one German language edition. See http://henryaltemus.com/series/series78.htm
There are several different formats but the most commonly seen books have the beautiful gold gilt designs on the cover. This fact also drives the collectors’ willingness to pay the big dollars. As to the point that these books are fairly common, there are presently 10 books from this series on Ebay and 54 for sale on ABE.
The absolute rarest format of these books (Format 6) is the Presentation Edition which was published only in 1889. This style is only on four of the titles of this series. The Presentation Edition is bound with fine bullion silk. Satin ribbons are stamped in gold and bound into the covers.
Today I am adding another Presentation Edition to the database. This is only the second one I have seen over the years. It is distinctly rarer than the other Dore books.
For more information about this series see http://henryaltemus.com/series/series78.htm.