What is it?
A 64 page softcover with a color cover and a black, white, red, and grey interior. It's not quite an adventure (at least in the sense of what WotC/TSR usually did/does in that category...). It's not exactly a setting book (at least in the sense of what WotC/TSR usually did/does in that category...). It contains a lot of NPC stats, but it's not an enemies book/rogue's gallery (at least in the sense of what WotC/TSR usually did/does in that category...).
It describes a sort of organization/ pocket domain known as the Carnival. The Carnival is over-all a benevolent organization: In fact, it's run by a celestial.
This book refers the reader to the following products/accessories: Champions of the Mists, The Nightmare Lands Boxed Set, Carnival of Fear novel, Domains of Dread, Ravenloft Monstrous Compendium III, and Van Richten's Guide to Fiends. You can live without them, of course, but for the fullest full story...
The book is constructed as three in-character narratives with the relevant game-speak off in sidebars. In the Carnival setting, a phenomenon called the Twisting makes a long-term resident's outer appearance match his inner nature. Besides already being reflected in the NPC descriptions, twenty examples for how to use the Twisting on PCs are included.
The first chapter is narrated by Tindal, the main barker. He likes the Carnival and conisders the Twisting harsh but fair. He is completely loyal to Isolde. This chapter covers most of the Carnival's more or less good guys among the regular troupers.
The second chapter is narrated by Madame Fortuna, the Gyspy fortune teller. This chapter discusses the Vistani's role in the Carnival. Fortuna is also on Isolde's side. She posits the theory that Isolde is literally an angel.
Chapter three is narrated by Professor Pacali, the barker for the Hall of Horrors. This is the chapter about the Carnival Troupers who could outright be called villains. Pacali hates Isolde and plots against her. He believes her to be a fiend.
The last chapter contains five scenarios.
Finally the absolute last page, gives stats for Isolde. She's a Ghaele, a variety of Greater Eladrin, a Chaotic Good Celestial. As a powerful extraplanar being in Ravenloft, she's effectively a demi-Lord with her own travelling pocket domain.
What's good about it? It's an entertaining read. As I said earlier, most of the book is in-character narration. Also, the chapters open with quotations from literary sources intended to set the tone. In a way, and I mean this mostly as a compliment, and it is not an accusation of anything like plagiarism or unoriginality, it feels as if WotC here took a page from White Wolf of this era's playbook in how to present a supplement.
What's not quite so good? The alleged adventures are more like long adventure hooks. There is a distinct lack of maps or special boxed text meant to be read aloud by the DM attached to the adventures. In this way too, it's like they took a page from White Wolf's playbook on how to present a supplement.
What the ....? moments: Cover copy that downplays Ravenloft nature of the product despite references to: Champions of the Mists, The Nightmare Lands Boxed Set, Carnival of Fear novel, Domains of Dread, Ravenloft Monstrous Compendium III, and Van Richten's Guide to Fiends.
Who should get it? Ravenloft fans; dedicated AD&D 2nd edition DMs looking for something novel to do to the PC group (check out the list of suggested Twisting effects starting on page 27); fans of the carnival noir subgenre of horror (I'm not sure how widespread the term is; I got it from a Nancy Collins column in White Wolf's Inphobia magazine).