This is one of those instances where the journey is far more interesting than the destination. I was really into the intrigue-heavy opening hour, with its eerie premise, cozy sets and settings (libraries, trains, hotel rooms), patient - often bordering on slow - pacing, and subtle menace. The whole thing's very sinister and atmospheric, and yet it also possesses a loose, almost silly tone that keeps the material light and playful.
For the most part, I think the movie balances this strange combination of moods reasonably well. But the same can't quite be said for the third act, which regrettably crosses over into "downright ridiculous" territory. There's admittedly some charm to that (for instance, hearing Frank Langella repeatedly yell "Mumbo Jumbo!" almost makes the entire portion worth it), but the forced theatrics, terrible fire effects, and largely unsatisfying final scene end things on a bit of a sour note for me.
Still, the majority of the adventure kept me invested, thanks especially to Johnny Depp's focused performance and Roman Polanski's assured direction. And even if I wasn't entirely satisfied with some of the later results, the ambience, buildup, and ambition ensured that I was always curious to see where it was all heading.
Grade: B+
P.S. I'm no expert on the matter, but shouldn't dealers wear gloves when handling old books? Or, at the very least, not blow cigarette smoke all over them?