Midnight Circus is a very strange supplement, as supplements go. Part setting book, part adventure, all kreepy circus coolness; it is a crossover book for all the major lines of the original World of Darkness (the book is from '96 I think, so that means 2nd ed. Vampire, Werewolf, Mage, Changeling and Wraith) that deals with an infernal circus and the supernatural creatures that inhabit and run it.
Anastagios Olde Time Lunar Carnival And Midnight Circus (a traveling carnival, circus and freak show ala P.T. Barnum) roams the World of Darkness, ensnaring gullible souls and luring unsuspecting people both supernatural and mundane in. Some leave. Most come back for more..
As a setting, it is a dark fantasy of circus horror. Scary clowns, freaks on display, haunting ghosts and an evil circus conductor from hell all contribute to a delightful aura of spokyness that screams out for being played while listening to Nick Caves' The Carney!
The downside to this book is that it is a total crossover thing.. Which isn't everyones cup of boiled leaves. But I loved it, and I've heard others saying they did too.
Overal, I give this bok five stars, because it hit all the right spots for me. Wonderfully written, great art, and a chilling story. I didn't really care much for the actual adventure provided in the book, but the setting material and the NPC's were brilliant, and I am definately going to use Midnight Circus in the future!