I have a "collection" of books, from a 1990's edition of Boston Yellow Pages (very thick) to the scrawny local books. I will probably pitch them when we move as I don't use them for paper piecing. Thought I would use them, but I tend to use copy paper instead. For string quilts, I've found adding machine tape rolls (available cheaply on eBay and come in various widths) work really well.
One question on using the phone directories...is there any problem with ink transfer to your fabric? Just curious.