motion control books

If you are a total virgin in the world of CNC, then the first thing
you need to read is "Jones on Stepping Motors" You can download this
document from the Metalworking.com website. When you understand what is
in that paper you will be well on your way.
Then read through all the links on the CAD_CAM_EDM_DRO homepage.
Then start browsing around the manufacturer's websites. Most of
them have good FAQ's and information that answers alot of questions.
Some have their own "books" on .pdf to download.
Once you have a decent understanding of the basics then spend some
money on a book if you still need it.