The image on the cover of Network Security Hacks, Second Edition, is barbed wire. The type of barbed wire pictured in the cover image was patented by Joseph Glidden in 1874. Glidden improved on earlier attempts at manufacturing wire fencing by fashioning sharp barbs, spacing them along a smooth wire, and then twisting another wire around the first to hold the barbs in place. Advertised as "cheaper than dirt and stronger than steel," barbed wire was immediately adopted by farmers in the American west as a way to control their herds. The days of free-roaming cattle and cowboys were soon numbered, but battles over barbs were fought both in court and on the ranch. Opponents called barbed wire "the Devil's rope," and the Cole Porter song "Don't Fence Me In" mourned this change in the western landscape. Barbed wire was here to stay, though-in addition to agricultural use, it has become a ubiquitous component of warfare and is a common feature of high-security areas such as prisons.
The cover image is a photograph from gettyimages.com. The cover font is Adobe ITC Garamond. The text font is Linotype Birka; the heading font is Adobe Helvetica Neue Condensed; and the code font is LucasFont's TheSans Mono Condensed.