The military aspects of the Civil War in East Tennessee have been so neglected in the literature that no book length work has emerged to substantially replace the material presented in Digby Gordon Seymour's centennial-era study Divided Loyalties: Fort Sanders and the Civil War in East Tennessee (East Tennessee Historical Society, 1963). A revised 2nd edition came out in 1982 [ISBN: 0941199002], to be followed by a 3rd in 2002 .
Learning about the touted new features of the 3rd (cover art at right), I recently investigated the advisability of upgrading from my rather tattered 2nd edition. Comparing the two most recent editions, it turns out that, while the 2002 release has redone maps, some new illustrations and color photography, staying with the older 1982 edition is actually the better move. The new cartography is not a substantial improvement, and, in the case of the Battle of Campbell's Station map, is arguably a step down. Strangest of all, many of the best full-page panoramic images of the Knoxville defenses from the earlier editions were either reduced in size for the 2002 book or absent altogether. The 3rd edition does helpfully provide a more current overlay map of modern Knoxville itself, as well as updated tour site locations and descriptions, but most of the changes appeared to be a simple rearrangement of the material. In my opinion, the 3rd edition (at $27.95) does not provide enough new material to justify replacing the 2nd, and in several key areas is actually an inferior product.
In terms of collectibility, what role the fact that each edition was subjected to major revisions plays in the ultimate value of the various editions is open to question [I wonder what Paul T. thinks]; but, in terms of the overall presentation and usefulness of the material, I would wholeheartedly recommend the 1982 second edition as the best of the three.