What book would you carry if you traveled like Alexander the Great did?

If I was to travel on a military campaign like Alexander the Great during that period, I would carry the book Anabasis by Xenophon. Though the book was unsubstantiated, it can be a source of study as well as inspiration while going on an extensive campaign. It details the adventures and trials that 10,000 Greek mercenaries experienced during their campaign in Babylon to their journey to the Black Sea. For those who go on military campaigns, it inspires those to keep on going no matter how hard the journey gets.