I was watching The Good, the Bad, and the Ugly the other night, which is my all-time favorite western and stars Clint Eastwood in his classic "The Man With No Name" persona. The film tells the tale of 3 less-than-savory characters seeking out buried Confederate gold in the American southwest.
unrelated sidebar - is there any better cinematography and musical score than this? :-)
General Henry Hopkins Sibley's 1862 Confederate invasion of New Mexico serves as a backdrop for the film which got me thinking about core and collectible books pertaining to that campaign. From my perspective, the standard work is still Sibley's New Mexico Campaign by Martin Hardwick Hall. It was originally published in 1960 by the University of Texas Press. First edition copies in fine condition are not easy to come by and command around $150 when found. Though it was long out-of-print, the book was reissued in 2001 and is now readily available. The dust jacket image is for this reprint but is very similar to the original. Hall also wrote The Confederate Army Of New Mexico, which is primarily a genealogical book that focuses on the personnel of the Army of New Mexico, comprised almost entirely of Texans, including some of the most prominent figures of the times.
It appears that the most desirable older title is Autobiography and Reminscences of Theophilius Noel, self-published in 1904 by the author, who served in Sibley's 4th Texas Cavalry. I found several copies for sale ranging from $200 to $450 for a signed copy.
There are several other modern titles that cover various engagements within the campaign and have become collectible due to their limited nature, including John Taylor's Bloody Valverde and Don Roberts' The Battle of Glorietta. This campaign has always fascinated me, occurring as it did thousands of miles away from the better known eastern battles.