Survival of the Fittest

There are three books I have read and enjoyed immensely, that share the theme of survival. These are: In the kingdom of Ice, by Hampton Sides; Into the Silence, by Wade Davis; and Unbroken, by Laura Hillenbrand.

In all three cases the protagonists are made to face the extremes of their environments and must rely on superhuman feats of endurance both physical and mental.

In the Kingdon of Ice is