With no apparent plan, filmmaker Errol Morris introduces us to four men who seem to have nothing in common. The movie is less about what these men do than it is about their impulse to strive and perfect. These four men are fascinating nonetheless, as they pursue tasks that initially look bizarre and pointless. If training lions to jump through flaming hoops rather than to attack their trainer seems like a useless way to spend a life, Mr. Hoover still possesses a strong and deep grasp of his craft and its history. And even chaos has its uses, as the robot engineer realizes. In its subtle way, this film celebrates the activity of studying and learning, and in a way that is sure to engage those who have the patience to stick with it.

It shares the joys of mastering a craft and indulging intellectual curiosity. Younger kids may desire more of a traditional narrative, but teens may especially like the movie's odd sensibilities. The movie leaves viewers with the notion that it could have focused on any four dedicated professionals, regardless of interest. Morris assembles his interviews and illustrations in a way that at first seems merely pointless and silly. He uses clips from old movies that often have nothing to do with what the speaker is saying. He also puts one subject's words over images of another's work. The connections he begins to make, though, are always compelling -- even more compelling are the ones we make ourselves, as we catch the men's contagious curiosity.