Minority Report is one of the few Williams scores where I've not been entirely sure on how it should be ranked. There is a strange unfulfilled feeling after listening to it; there isn't the lasting memorable melodic content or vast swathes of an accomplished composer going off in a entirely radical new direction, but the sure feeling that it's an accomplished piece of work worthy of recommendation. Steven Spielberg describes the black and white nature of the score, although I'm not entirely sure what to make of that since Williams' orchestral palette is typically varied. In fact a few vocal and synthetic enhancements (all effective, but almost subliminal) increase the colour in his composition. One very notable difference to recent efforts is that Minority Report is much less broad sounding, there is an intricacy and busyness to the orchestration, notably during the more exciting sequences, that does suggest the Williams of old.
As mentioned, there isn't really a main theme to Minority Report. Sean's Theme is haunting and very low key, but even in its nominal cue is brief and somewhat underdeveloped. There is a suggested Herrmann element to the score, due to the little motifs that Williams uses to build up the some of the suspense and the few action moments. This doesn't quite stretch to the pronounced pseudo-minimalism of AI, but the melodic fragments are just that, little snatches of melody that don't resolve or really go anywhere, but are simply there to be played with. I'd guess that the most memorable cue for most is the thrilling Anderton's Great Escape which follows in similar style to the Zam the Assassin cue from Attack of the Clones. However, it is considerably superior by being better constructed, more concise, more intricately orchestrated (but not distractingly so) and consequently sustains the excitement and tension far better than its Star Wars test bed.
Another strange feature of Minority Report is a dichotomy of the original and "sounds like..." moments. The tone and overall feeling is somewhat unfamiliar Williams territory, but many of the components can be found in other works. The chasing strings of the opening Minority Report (a motif that is repeated and augmented in later tracks) as well as some of the more haunting and melodic material both suggest different aspects of AI, while Spyders does recall the slightly silly villain march from Superman (but sounds more serious here), as well as the aforementioned Anderton's Great Escape both from Attack of the Clones and the finale to Williams' Trumpet Concerto.
Despite giving the impression of being a patchwork of other Williams, Minority Report still curiously manages to retain a certain identity of its own. It has a constantly dark and foreboding atmosphere that is rare in Williams works. Schindler's List may have been disquieting, but it has a human elegance when Minority Report is emotionally a little stand-offish. In the ideal world of total artistic isolation, it is an effective piece of work, although a couple of the slower tracks could have been left off for a better paced album. The highlights are definitely the action, the suspense is always effective, but musically varies in quality from impressive to a bit dull, while the quieter moments seem to pass by almost anonymously. Of course it's far better than anyone else would have written and I suspect is stunning in the film, but overall lacks the edge to push it into the Williams essential category, brilliant though it occasionally is.
Rating ~ 
Total Time ~ 73:55