Jack Zinn's The Battle of Rich Mountain (Parsons, WV: McClain Printing Co., 1971 (OP). pp. 51, maps, notes, biblio) is a modest pamphlet that relies on few primary sources beyond official reports. Although footnoted, the publication appears to be directed toward the tourist and general reader audience. It came to my attention while I was searching for a reasonably priced copy of Zinn's R.E. Lee's Cheat Mountain Campaign (Parsons, WV: McClain, 1974 (OP). pp. 230) -- a more serious piece of history.
Although I was recently able to upgrade my own Battle of Rich Mountain from photocopy to original at little expense, copies of the pamphlet routinely go for $25-$50 on the secondary market. I believe one would be hard stretched to justify paying anywhere near the upper range of that scale for it. There is very little information contained therein that you can't get elsewhere from readily available sources. The maps are a bit crude and, moreover, their potential usefulness is spoiled to a large degree by a lack of scale. Reading the pamphlet certainly isn't a waste of time, but limited book collecting funds would be better spent elsewhere, in my opinion.