The Long Walk, a book by Slavomir Rawicz
Cavalry officer Slavomir Rawicz was arrested by the Red Army in 1939 during the German-Soviet partition of Poland and was charged with espionage against the Soviet Union. He was tortured badly, convicted in a farce of a trial and sent to the Siberian Gulag along with other captive Poles, Finns, Ukrainians, Czechs, Greeks, and even a few English, French, and American unfortunates who had been caught up in the fighting. He endured about a year in the prison camp before he and six companions made an escape attempt. This book is a detailed description of their trials and hardships as they journey south through Asia, on foot, for thousands of miles. This brings them through the blistering heat of the Gobi desert and the chilling winds of the Himalaya.
Some doubt as to whether Slavomir's account is true or not has arisen. At one occasion the group of escapees is claimed to have gone through the Gobi desert without water for almost 12 days, which would be a feat even without the scorching sun overhead. At any rate the book is an amazing tale of what man can do for freedom, and definitely a recommended read.
An interesting tidbit found in the later part of the book is when Rawicz and group come upon two creatures that, unmistakably, are Yeti, or Abominable Snowmen. They watch the creatures at a distance for over two full hours, before leaving them to continue the journey. Whether this adds or detracts from the books credibility is up to you to decide.