Between 2011-2016 I published and sold these ebooks on jstorimer.com. The content has not been updated in quite some time and I have no intention to do so in the near future. It's being shared here for free for anyone who wishes to read it.
The content may be out of date with the current version of Ruby as it was written against Ruby 1.9. That being said, all code samples should still run as these system programming APIs don't tend to change much over time.