Two books have been seen in the format shown here, Fanchon and Rubaiyat of Omar Khayyam. It is unclear as to which series these books belong to but they certainly do belong to one. The book which has a soft leather binding, is easily dated however. The title page imprint is Henry Altemus not Henry Altemus Company. This indicates a pre-1900 printing. In addition the frontispiece is dated 1899. Thus there is no question that it is an 1899 book.

Now the issue is which series listed both titles and was published in 1899.

Here are the possibilities:
Series #48 Beauxarts Series-Later numbering
Series #130 Marqueterie Series
Series #143 Petit Trianon Series
Series #163 Sanspareil Series
Series #180 Vademecum Series-Later numbering

Of interest is that all of these series are “publisher’s series” and none list a soft leather edition in 1899.

Most likely this book came boxed (less likely with a dust jacket). The box or jacket will undoubtedly give the series name. Hopefully one will turn up sometime.