The Long Walk by Slavomir Rawicz
Polish cavalry officer Slavomir Rawicz was captured and imprisoned by the Soviets in November 1939. Since he spoke fluent Russian (his mother was Russian) they assumed he was a spy and tried to torture a confession from him. He resolutely refused. Eventually he was tried, convicted, and sentenced to twenty-five years hard labor. After trekking several thousand miles to Siberia, he wound up at Camp 303. He slowly formed a plan and the nerve to escape from the camp. He would go south to India, another trek of thousands of miles. Recruiting six other prisoners, they hid supplies and waited patiently until they could get away. The last two-thirds of the book describes their desperate travels through Siberia, Mongolia, the Gobi Desert, and Tibet on the way to freedom in India.
The story is highly dramatic and well-told. The tale is an amazing travel log and an astonishing witness of human perseverance against so many difficult and seemingly insurmountable hardships. Starvation, thirst, injury, and exposure were constant enemies. Moments of humor and hope kept them going, along with the memories of life at home. The implicit comfort that at least Rawicz survived to tell the tale helps.
The book was made into the 2011 movie The Way Back directed by Peter Weir (of Master and Commander fame).