A lot of 4 Richard North Patterson paperback novels, as follows:

1. Eyes of a Child, paperback, 1998, 0-312-38162-2.   The pages have some yellowing.  
2. No safe place, paperback, 1998, 0-345-40477-7.   The pages have some yellowing.   There are some small stains on the outer edges of the pages.
3. The Spire, paperback, 2009, 0-312-94369-5.
4. In the Name of Honor, 2010, 0-312-94640-1.  The pages have some yellowing.   The spine is broken in the center of the book but all pages are intact and readable.