From publisher blurb:
Stretch Your Reality
There are waking dreams, there are active hallucinations, there are feverish visions that cannot be classified. And then there are the metaplanes, an adrenaline-fused combination of all of these, and more. Everything you dream of, everything you fear, everything beautiful and everything grotesque can be found out there. If you travel to the planes, you may lose your life, lose your mind, or if you’re lucky, just lose your way. But you may find hidden secrets of magic and perhaps make powerful allies. It’ll be a change from everyday life in the sprawls of the Sixth World, but may well be worth it. Are you ready for something entirely different?
Aetherology offers a grand tour of many metaplanes—the wild, the weird, the dangerous, and the everything in between. Prepare for mind-bending journeys to alternate realms of existence and the opportunity to encounter a new host of dangerous spirits and creatures. With rules on astral phemonena and new powers for the critters detailed in the book, Aetherology offers a whole new twist to your Shadowrun games.
Aetherology is dual-statted, meaning the spirits and creatures inside can be used in both Shadowrun, Fifth Edition and Shadowrun, Twentieth Anniversary Edition.