From publisher blurb:
The demigod Celestial Heroes have conquered the world and raised civilization to precipitous heights but only YOU can save it from destruction!
On the eve of evil's twilight as malevolence nearly became undone on the decopunk utopia of Askis the terrible machinations of rogue mad scientists instilled a vein of corruption throughout the populace. Though they are few these malcontents are irreprensibly vile and in tandem with the foul minds that touched their nascent souls with evil, the world once more needs heroes.
You are one such hero.
What's in the Book of Celestial Heroes?
The goody-two shoes twin of the [Book of Exalted Darkness]
Two new classes--the Exemplar (a hero all about glory) and the revised Feywalker (when flight and fancy are more important)--along with holy archetypes for every class
Holy spells
Holy rituals
Holy feats
Heck, there's even a holy hand grenade (which explodes on the count of 3--not 5, but 3)
The decopunk utopia world and Spheres of Askis, great works the PCs must bolster to save civilization from destruction
Tailored magic items that become more powerful as an adventurer gains prowess
Equipment and inaequa-technology that run the gamut from flashlights to jetpacks and locomotives (along with vehicular combat rules)
All the poisons plus a few new ones, diseases galore, and extra madness and insanities
Six powerful mad scientist villains each with their own lackeys and lairs joining more than 50 NPCs and monsters
Searching the River Styx, a scaling adventure for PCs of 3rd-16th level and just the right thing when the group goes down from an evil TPK!