Hmmm...
I read lots of castle themed books, so I'll probably just go by 3 categories.
Fantasy
1. Everything Tolkien of course
2. Chronicles of Narnia
3. The Inheritance Series (Eragon, Eldest, and eventually the third book)
4. The Pendragon Cycle - It's an interesting take on the King Arthur story. Great series. It's made up of five books: Taliesin, Merlin, Arthur, Pendragon, Grail. Highly recommended. It sounds kinda historical. For example castles and timber forts are called Caer (insert name of fortification here). I am currently reading Arthur and am looking forward to the next two. Its written by Stephen R. Lawhead.
5. The Binding of the Blade Series - It like a mixture of Tolkien's and C.S. Lewis's books combined. Currently it's made up of two books, Beyond the Summerland and The Bringer of Storms. I'm guessing the series will end with three books?, anyway not sure. Very cool books; I am eagerly awaiting the third installment. It's written by L.B. Graham.
6. Malory's Le Morte D'Arthur - started reading it, but never finished it. Great battles in it from what i have read.
Note! This book is probably not for younger aundiance than 10-13?.
7. Robin Hood? - Not sure if it goes with historical or not. Must reads though.
8. King Arthur? - Not sure if it goes with historical or not. Must reads though.
9. The Story of Roland - ancient book not sure if it is even in print anymore, but a fun read. The book is very much the story of a Lancealot-ish knight named Roland. The battles are fun because a famous seem to take on huge armies with the attitude of "I'll take all out" sort of thing
. Kinda sad ending though.
Historical fiction
1. Ivanhoe - great book by Sir Walter Scott. A must read.
2. The G.A. Henty books from the medieval era.
3. The Last Kingdom - have not readit or got the book yet but desire it greatly. Great book from what I have heard.
4. The King's Shadow - A Chronicaler follows the event of the year of 1066 from King Harold's (saxon) point of view. Written by Elizabeth Alder.
5. Men of Iron - written by Howard Pyle, it follows the story of a young squire on his journey to knighthood to avenge his father's disgrace.
Nonfiction
Unfortunately I do not have very many of these...
1. Medieval Weapons and Warfare - written by Terence Wise. Used it in soooo many reports and essays I've lost count. Very nice book.
2. The Lord of the Rings: Weapons and Warfare - written by Chris Smith. If you don't have a copy, get one. I know it is not historical but the stuff used in the movies was actually functional. They even have a dictionary in the back of parts of weapons and armor. I practically droolled all over this book seeing the weapons and armor with detailed explanations...just joking about the drool
. I have actually used it in a couple of essays.
I definitely wish I had more nonfiction medieval themed books.
Finally the end... may have forgotten a few boks here and there, but oh well.
Sorry for the extremely long post...I don't post much so words tend to accummalate...