This is a great book with two flaws: about 50 too many pages and a partly anti-climactic ending. The story is a journey through Cold-War Europe with several generations of historians researching the real Dracula.
Kostova's writing style is superb. Her concept is to tell many stories simultaneously through the point of view of some characters telling stories to others, creating layers of stories within stories. The writing style of the book is relaxing and comfortable. It's a thriller, and has been compared to The Da Vinci Code - but has completely different pacing. This is not a page-turner. The Da Vinci code's pacing is like a hit pop-y song you work out to; this is like lounging around with a favorite, mellow song. Or like watching a nature documentary that's too fascinating to turn off - as opposed to watching 24. With The Historian, you can enjoy the writing, legend and lore, characters, and settings enough to forget about the frustratingly meandering plot.
The ending bugged me a bit. Pages could have been cut from the rest of the book, but the finale still felt rushed. And a few questions weren't answered adequately. She had a lot of great ideas and all the information to back it up, but I don't think she pushed it as far as it could go at the end.