Dear Mr. Cornwell,
What are your most used historical sources for STONEHENGE, The Warrior Chronicles, and Grail Quest? Admittedly, I am envious that you have the British Museum and the University libraries to hunt in, but are there any special sources you had to own and could not write without?  I enjoy scrummaging around in British history and British historical personalities, and I would think such sources would make fascinating (if dense) reading. Thank you for all you have written and (we pray) will write.
S P Hawk