The Development of the Modern Flute by Nancy E. Toff Readable copy. Pages may have considerable notes/highlighting. ~ ThriftBooks: Read More, Spend Less
Excellent book on the developments in the modern flute. Particularly the development of technical mechansims and tuning in the 19th and 20th centuries, especially Boehm's flute.
It does also look briefly at flutes of the Middle Ages, Renaissance and Classical/Baroque periods.
Shame however the Rudall Carte & Co. Radcliffe's Model flute is mistakenly shown as a RC&C Guard's Model, ditto its mechanism diagram.
I would also recommend Philip Bate's Flute history book, Ardal Powell's Flute history book and Baine's "Woodwind Instruments And Their History". Also Solum's "The Early Flute"