I've delayed a bit, writing about this book, because I have some ambivalent feelings about it.
Don't get me wrong, I love Eco, and admire his writing greatly - for its prose style, its structure, its meticulous research - the book more than deserves 4 stars. It's a very worthwhile read.
However, time spent reading this book is time spent in the company of venal, reprehensible men. It's not a pleasant experience. Eco is theorizing, recreating the character of the bigoted, self-serving individual who may have created the infamous 'Protocols of the Elders of Zion,' and he, and everyone around him, is corrupt and nasty. However, this character is not unintelligent, and in his philosophizing, often speaks with Eco's voice... but then turns around and says something just awful - it makes for an interesting but challenging read, figuring out the author's intentions.
I also have mixed feelings about the plot device of having the narrator be an amnesiac/split personality, trying to piece together his identity and past. It was interesting, yes, but it wasn't necessary to the story, and I felt it was also too similar to the device used in 'Queen Loana.' Much like 'Loana' as well, the book is 'illustrated' with historical engravings 'from the author's collection.' The images are fascinating, but I wish that more specific historical context/credit for them had been provided.