The Anarchy was a War between two Norman Nobles and their vassals, with claims to the English throne: Empress Matilda, and her son, Henry I, and on the opposing side, was Stephen of Blois. Can some one recommend a good book on this war, and explain why it is so unknown? Thanks!
Follow up question, why is it called "The anarchy," instead of "The war of English succession," or something along those lines?
I wouldn't say that there's very little about the anarchy out there. Quite the contrary, historians are very much interested in it. Matilda's role as queen and how it is an example of the role of women as peacemaker within northern French and English society. I would contest Rittermeister's assumption about "high feudalism." As you can see in numerous threads, "feudalism" and the attendant narrative has been rejected by most historians. I would also say that the standard narrative of English history is more like, gradual centralization of England under Wessex in response to the Viking invasions > 1066 > Slow development of Common Law with particular emphasis on Henry II and the formation of the Angevin Empire > The loss of continental holdings under John and the signing of the Magna Carta (despite it's initial unimportance) > The seeds of the House of Commons and expansion into Wales and Scotland under Edward I > 100 Years War. All of this with a near constant emphasis on the contentious relationship between the crown and nobility. I don't want to step on people's toes, but I also don't want to spread misinformation.
There was an In Our Time episode about the anarchy a while back and the website has a useful bibliography.
http://www.bbc.co.uk/programmes/b01nl963
There has been a lot of recent research as well. A quick International Medieval Bibliography search for empress Matilda sends back 57 hits with a number of items published in the last few years.
You can't go too much wrong with the Yale English Monarchs Series as introductory reading. Edmund King's King Stephen came out a few years back, and though I haven't yet read it, I've heard nothing but good things about it.
If I had to venture a guess, it's because the Anarchy, a period of massive social disruption smack in the period of supposed high "feudalism," doesn't fit well with the conventional narrative of English history. All too often, it seems to go Anglo-Saxons > Norman Conquest > Crusades > Hundred Years War.