I would read Robert Utley's biography:
A Short and Violent Life (
http://www.amazon.com/dp/0803295588/?tag=civilwartalkc-20). That's the gold standard. I have at hand Maurice G. Fulton's
History of the Lincoln County War, and has been noted, most of the books are about the Lincoln County War and include information on Billy the Kid....this one has been around since 1968. Fulton researched it for years and this was only published after his death. It's my Bible. I know a lot of people prefer Frederick Nolan, but there are some things he just blew it on, and I happen to prefer Fulton. I would also recommend
To Hell on a Fast Horse by Mark Lee Gardner just because it's fun....and it brings up some new research. I'm embarrassed to admit I had a really good book on his youth (including the bit about his abilities as a student) which I used in a grad school paper--and I've lost it. I can't even find it online to cite it. I know it was fairly short (no pun intended) and the dust jacket was blue. If anyone does find it, let me know.
Just to explain--as a child I was obsessed by the whole Lincoln County War. My dad sold mineral and feed out in the Lincoln County area during WWII, and a number of the older ranchers he sold to( he was a history nut, like his daughter!) were either alive during the LCW...children....or their parents were. He pumped them relentlessly for information. When he realized what a little gem I was, he indulged me with numerous vacations to Lincoln County....we stayed at the Wortley Hotel...we walked the streets of White Oaks and Lincoln as he explained what happened...it was amazing. Then, after I married, my husband and I had friends who lived in the Hondo Valley. One of them was a cowboy artist, and we joined with him and a couple of others in putting in a gallery. Lincoln was not yet a National Historic Site, and they actually leased the West room of the Tunstall store to us and GAVE US THE KEY. I spent hour upon hour there--with my trusty copy of Fulton's book. I can't even begin to tell you how excited I was when--cleaning out the house we were renting in nearby Alto--I found paperwork relating to Jimmy Dolan's role in the war. He was an ancestor of our landlord! It was sort of one of those Diane things.
So....I'm not just someone who's sort of read about it....I am about as close as you can get to someone who was there
TMI, I know.