In 1888, as news of the attacks by the Hatfields on the home of Ran'l McCoy on New Year's Eve spread, John Spears, a New York City newspaperman, came to the Tug Valley to report on the violent incidents. He found himself in the home of Ran'l McCoy, and the version of events told to him came by way of Perry Cline, Pike County prosecutor Lee Ferguson, and Ran'l McCoy himself. The writings of John Spears, for better or worse, became the basis of all Hatfield McCoy feud writing to follow. If you want to understand how the feud story came to be, this is the place to start. This version has been carefully annotated to show how it supports and deviates from the factual record.
I have read a few books about the Hatfield and McCoy feud and while this doesn't have the depth of detail and interpretation as many of those, it is (I understand) the first account to be written. First published in 1888 it reads very much as you would expect, it's short and to the point, providing the core elements of the feud and the basis for most subsequent accounts. Ryan Hardesty states in the introduction that as Spears got his information from the McCoy faction, he has annotated the text to add clarifying points as he see's it in relation to statements Spears has made. Overall it's a quick read and interesting to get back to the earlier source material. Worth a look.
This book was different because it was written as it was happening. You got better insight as the author was able to speak with the participants while they were alive. A much truer book since it was firsthand knowledge.