From publisher blurb:
Take your next adventure to the open skies and explore totally uncharted territory. Learn about the flying cities that escaped an necromantic war and dive into the clothwork fiberpunk aesthetic of Cirro, the City of Vapor. Find unique items and monsters only a skybound adventure can provide, from levitating cirrosilk garmets to massive terrors.
You'll find the following within this compendium's 27 pages:
3 pages of lore about the nature of the open skies, including its weather, roaming monsters, and floating cities
5 pages about Cirro, a fiberpunk city on clouds
18 adventure hooks and encounters for exploring the open skies and Cirro
1 new player ancestry detailing the sky-touched Cloudlings
1 new monk subclass for adventurers who follow the Way of Dancing Wind
23 sky-themed items, from the fibromancy-woven extension arms to the legendary warfan of the wind
9 skybound monsters, from the elemental-touched cloud dragon to the carnivorous cloud known as the fogged devourer