THis large 1866 edition by Fairfax press of Harper's Pictorial History of the Civil War is quite common and the books often have a good amount of wear as yours do. The cover of your book is important to the value as good old facsimile abound and sell for higher amounts than the originals in fair condition. An 1866 example in very good shape has a documented rare book value of 80-90.00. In poor condition the values come down to 30 and 35.00 and sometimes less depending on the severity. There are currently 8-10 on the Worldwide market and 50 some reprints so the market is full now. If you were thinking of selling, a local dealer or venue may do better where the competition is less fierce than a rare book seller online.
Best wishes, Dori
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