Knitting book library

I want to buy some must have knitting books. I have most of the Debbie Bliss books. Could anyone recommend good technique books?

If you want to do a Search, lots of existing threads that touch on this in the General Knitting forum. One that might offer insight:

‘help! best knitting reference book & online yarn qualit’

http://www.knittinghelp.com/knitting/forum/showthread.php?t=46913&highlight=book

cam