Black Book is the first Dutch film Paul Verhoeven has made in a long time. It has a tone that is much less arch than his American films (particularly his masterpieces RoboCop and Starship Troopers), it's also much more morally ambiguous. It's most immediately comparable to Starship Troopers, a theme of which, as Verhoeven discusses on that film's (generally fascinating) DVD commentary track, is that war makes everyone a fascist.
This theme applies to Black Book to an extent, but I think it's more accurate to say that in Black Book war makes everyone's morals quite a bit more elastic. The film takes place in the last years of World War II (the Russians have taken Berlin) and it follows an attractive young Jewish woman from being in hiding, to an attempted crossing into liberated territory, to a Dutch underground resistance group. The majority of the film is about how she negotiates her genuine affection for a Nazi commander, who seeks to end reprisal attacks against the Dutch insurgency, with her loyalties to the underground, which harbors fantasies of the Nazi executions the end of the war will bring.
I'm at a loss for things to say about the movie that don't give away any of its substantial surprises. It reminded me, though, that as much as I love RoboCop and Starship Troopers, and as much as I enjoy Basic Instinct and Hollow Man, that I still have not seen any of his Dutch films. I want to change that this summer.
Incidentally, here's a shot from Black Book I find emblematic of Verhoeven's American productions. The woman on the bike is Rachel, our hero. As the bike passes Nazi soldiers she smiles and flirtatiously flashes some upper leg. There's no narrative reason for this. She's a Jew in hiding, and the previous night she was warned to get out of Holland as quickly as possible. The leg flashing is an inexplicable mixing of eroticism and violence that pervades so much of the man's work, and seems to make a lot of people uncomfortable. Anyway, it's a pretty great movie.