This is a very rare Altemus advertising cover from 1890. In 1889 Altemus published the six titles of the Dore’s Masterpieces Series. (http://henryaltemus.com/series/series78.htm). All six oversized volumes were published until 1903 in a number of different formats. Because of the beautiful Gustave Dore illustrations, these books are always in great demand and sell for a premium.

This advertising cover pictures Format 1- Volume 1 in the series. The other books are listed at the top of the envelope. Die Dore Bibel Gallerie is a German translation of Volume #1 and was included in this series beginning in 1892. (Thus, at that point there were seven titles in the series.)

In my opinion this is one of the rarest pieces of Altemus ephemera.