Ice Station Zebra by Alistair MacLean

UNDER THE POLAR ICE-CAP...

The atomic submarine 'Dolphin' has impossible orders: to sail beneath the ice-floes of the Arctic ocean to locate and rescue the men of weather-station Zebra, gutted by fire and drifting with the ice-pack somewhere north of the Arctic circle.

But the orders do not say what the 'Dolphin' will find if she succeeds - that the fire at Ice Station Zebra was sabotage, and that one of the survivors is a killer ...