From the introduction: Acting like great rivers of magical energy that traverse all known corners of creations, ley lines are the veins and arteries of reality. Ley lines converge into vast networks at geographic and cosmological features both great and small, and provide great knowledge and power to those willing to tap into them. Although Everyman Minis: Ley Line Qualities explores the topic of ley lines in depth, the basic rules regarding ley lines can be found in the ley line section of Chapter 6 in Occult Adventures.