Latest working link to International Relations by Joshua Goldstien. It is 2013-2014 edition.
http://www.mediafire.com/file/jbh7s9...se+%282%29.pdf
Note: This is the most recent edition I have found in soft form. In market, You may find latest edition in market if required.
It is highly recommended book for IR and being written by foreign author its contents are not according to FPSC syllabus. You just need to find relevant topics yourself and study them.