Value of John Ruskin Books?

The missing spine material may be a killer, although a book dealer might have to see the individual volumes to say how much that and plain old wear have hurt the value.

Sadly, a great many hardbound books published between 1850 and 1950 have very little worth, even if they're still meaningful to present-day readers.

AbeBooks shows several volumes of Modern Painters offered at $10 each, but only one complete set, in fine condition (some leather rubbing marks) for $197. There are, however, no offers on any of them. Only a bid or recent sale of a volume nearly identical to yours in terms of condition tells you an actual value of what you have.

I'd scour AbeBooks and ebay seeking identical volumes and watch for bids and sales.

If they are nice bindings, they may have some value, but being worn is inevitably going to lower the price. Wiley was an educational publisher so the editions may have less appeal to a collector, unless they are library editions. They would be more attractive if they were the complete works which is about 26 volumes. 19th century editions go for about $25 dollars a piece last time I looked, so you may get a reasonable deal on them.