I'm a history nut also, I thought about becoming a History teacher, but never did, I took U.S. history in collage at one time and I already knew everything the teacher was talking about, it's funny, while taking history at collage, one day after class the teacher called me up to his desk to take a book of his home for me to read, I look at it and said to him, I already have it, he look suprized. HA !

Enough about me, here's some books I have in my library on the U.S. flag's history.

Masonry and the Flag by John W. Barry
an interesting book on how the Masons help out during the Revolutionary War and help to design the first flag and the American seal.

Betsy Ross's Five Pointed Star, Elizabeth Claypoole, Quaker Flag Maker, A Historical Perspective by John Balderston Harker

and I order this one off of a flag site so many years ago,

Shattering an American Myth: Unfurling The History of The Stars and Stripes.
by Henry W. Moeller-----This is a interesting book, it came out in 1992, claims the origin of the flag came from Naval Striped Signal Flags.