In defending your systems against intruders and other meddlers, a little knowledge can be used to make the bad guys--particularly the more casual among them--seek out softer targets. Counter Hack aims to provide its readers with enough knowledge to toughen their Unix and Microsoft Windows systems against attacks in general, and with specific knowledge of the more common sorts of attacks that can be carried out by relatively unskilled "script kiddies." The approach author Ed Skoudis has chosen is effective, in that his readers accumulate the knowledge they need and generally enjoy the process.