Such a topic would work today, because of what you know. Efficient, tense, typical from this period of cold war and large scale possible threat from the Eastern Block. Sharp thriller from a Alistair Mc Lean's novel that I have not read.... The ending is predictable but this remains spectacular, not too much talkative, and with an exciting climax too. Not the most iconic John Sturges' stuff but I repeat, good pro job for this director.