Impractical Magic, Volume 2
[This tome covers the nature of dead magic zones.] During an era called the Time of Troubles, a good many changes befell the world, not least of which was the fracturing and reassembling of the source of all magic called the Weave. Though much of the world has recovered from that era, some sites remain scourged of magical power. Cut off from the Weave, they nullify all magic and spellcasting nearby...