You'll never find a book that describes every key and value in the registry, accurately or not. There's just too many of them and there are too many values that only some developer in the dungeons of Microsoft know the purpose.
Yes, you can check the Run and RunOnce keys in the registry to see if a program is running that you don't know about. But doing so doesn't ensure that a back door isn't installed. There are many other ways to install spyware, and the registry is just one of them. I'd consider using software such as Ad-aware from LavaSoft.com to snoop these plagues out.
This was first published in July 2003