"Quilting for Dummies" if she's just starting. Covers everything from fabric, thread and needle choices, seaming, batting, quilting. I picked it up about a year or so after I started quilting and found easier ways to do stuff and bad habits that I aquired that I didn't know were bad habits.
After that - a book with several easy patterns in it. Perhaps a Log Cabin book as there are so many different ways to put the same block together. Also teaches pretty elementary piecing that given the right color choices/placement can still have that WOW effect.