Art Nouveau era book covers all tricked out in gold. American. Margaret Armstrong, designer (1867-1944).

"Millionaire Households and their Domestic Economy."
“Millionaire Households and their Domestic Economy.” Mary Elizabeth Carter, author. Published in 1903 by D. Appleton And Company, New York. In the public domain. via http://www.johncoulthart.com/feuilleton/2010/02/01/margaret-armstrong-book-designs/
"Days Off and Other Digressions."
“Days Off and Other Digressions.” Henry Van Dyke, author. Published in 1907 by Scribners, New York. Image © 2008 The Athenæum of Philadelphia. Fair use license. via http://www.athenaonline.org/Artbound/case7.html
"Adzuma."
“Adzuma.” Sir Edwin Arnold, author. Published in New York by C Scribner’s Sons in 1893. Image © 2019 Copyright The New York Society Library. Fair use license. via https://www.nysoclib.org/blog/art-book-margaret-armstrong-and-her-bindings

Fairies that leap off the shelf and into your dreams. . .selected covers from Andrew Lang’s “colored” fairy tale books from the turn of the last century. Henry Justice Ford, illustrator (1860-1941).

Green Fairy Book. Published in 1892.
Green Fairy Book. Published in 1892. via pinterest.com.
Crimson Fairy Book. 1903.
Crimson Fairy Book. 1903. Image via http://ginandbird.tumblr.com/post/42896728024/cookedheads-via-beautiful-bindings
Violet Fairy Book. 1901.
Violet Fairy Book. 1901. via https://twitter.com/iulillylibrary/status/1006226910190493696.

All images in the public domain. . .. there are quite a few more for you to find via google but the resolution wasn’t high enough to use here. Enjoy!