From the publisher's website:
Runes — an ancient form of writing often linked to strange and magical powers. In history, runes are nearly-two-thousand-year-old alphabets whose origins remain shrouded in mystery. In legend, wizards, shamans, and warriors use runes to imbue places, items, and even people on which they are inscribed with fantastic powers. Runes, it has been said, hold the power to foretell the future and even to bring the dead back to life.
Although you can clearly see the graphic influence runes have in the Pathfinder Roleplaying Game — with rune-like symbols appearing in many pieces of art — they enter into the core rules only through the cleric’s rune domain. Although many campaign worlds hint that runes contain some kind of primeval power, there is nothing in the mechanics to back those concepts.
The Genius Guide to Feats of Runic Might presents a way to use runes to bring a little “old-school” magic to a campaign — magic that is available to anyone who takes the time to study runes and master their creation.
Runic feats all involve using magic symbols and glyphs to create magic effects. The more such symbols you have mastered, the greater benefit you get from all your runes. The process of creating (or drafting) runes and gaining magic benefits from them is known as runecrafting, and it is an art similar to, though distinct from, spellcasting. Unlike spellcasting, with determination and patience anyone can learn enough runecrafting to make practical use of their power.