He wrote 2 books about how he defeated Batista (the cuban dictator) armies . He fought majorly in the Mountains of Sierra Maestra . In the book he depicts the geography of the region.When he was in charge of the economy of Cuba he knew how to use the geography of Cuba for our own interests. He was by no means perfect but his knowledge helped building our economy. An example was the proyect "la voluntad hidraulica". Is a great network of dams in Cuba . Even after his dead we are finishing " el trasvase este oeste" I don't know if you knew that Cuba suffers from drought in the central region. So the " trasvase " is a colosal proyect to bring water from the east to the west. That Will allow us to develop farming in the central region .There are many other examples.