As courtroom dramas go, this is unsurpassable: 'JFK', 'Anatomy of a Murder', even Spencer Tracy's later masterful performance in 'Judgement at Nuremberg'...none are quite as good as this. What makes it remarkable is that the trial of John Scopes for teaching evolutionary theory in Tennessee happened in 1925 and ought to feel like old history - but it isn't! America is still full of creationists who believe every word of the Old Testament is literally true - in many polls, it is the MINORITY in the States who side with Darwin.
In fact, this film is very balanced in terms of faith and science: it doesn't kick the Book of Genesis out completely. From today's perspective, here in a largely secular UK, parts of it seem a little quaint, not least the final revelation that Spencer Tracy's defence lawyer is actually a bit of a Bible buff deep down. Clarence Darrow, the real lawyer on whom Tracy's character is based, was rather less sentimental. I also suspect that Gene Kelly's big city journalist was intended at the time to be unpleasantly cynical, but by today's standards he seems spot on - his parting line is brilliant!
Of course, the film plays a little fast and loose with what happened in the real trial (which is presumably why all the names have been changed). It is still, however, a masterful piece of work, with scintillating dialogue and real drama - as topical today as when it was made.