I haven't come up a W. W. Denslow binding in a rather long time. He did quite a bit of work for Rand McNally from 1896 - 1898, but aside from a handful of titles that are a little more common, the books are difficult to find. The majority of his covers are easy to recognize when you see them, due to a distinctive sense of imagery and type style. Certain elements are often repeated, such as coats of arms - in this case, the double headed eagle of the Romanovs of Russia.
This is For Her Life, from 1897, written by Richard Henry Savage. Denslow did covers for several Savage titles, of which I have 4. This particular cover is interesting for being very subtle. The book shows little wear, but the light grey used for the imagery is very pale against the background. This is a wrap around cover, and Denslow's seahorse is present - though difficult to see - in the band of grey water below the boat.