Understanding
Rigs and
Rigging by Richard Henderson - out of print but can be had used for 3-5 times its original cost on Amazon. excellent book on
Rigging
Sail Trim: Theory and Pratice by Peter Hahne very informative soup to nuts book on sail trim and much related info.
For you O'Brian/Aubrey fans; Cochrane: The Real Master and Commander by David Cordingly. Cochrane is just as facinating as Aubrey only REAL. A must read, a true rebel in the Queens Navy. Had a pair so big he didn't need a boat to go sailing. I read it in 2 days (had to nap, was getting cross eyed).
The finely Fitted Yacht by Ferenc Mate for those that just can't stop tweaking thier boat (over 200 projects - hows that for a to do list).
Knots and Ropework by Eric C Fry for when your mate is feeling kinky.
I'll have more once I check the library on the boat.