This is a fairly light-weight introduction to what spyware is, what it does, and how to detect/block it. Mostly, it refers to other tools rather than giving any new info, but it does have a reasonable overview of different tools.
You can download it from the following link: https://packetstormsecurity.com/files/download/34695/Complete_Spyware_Whitepaper.pdf
Source: https://packetstormsecurity.com/files/34695/Complete_Spyware_Whitepaper.pdf.html