To get a feel for Mongol history, you might start with a feel for its climate and setting. Imagine sustaining a horse-based society in open plains colder than Nome, Alaska: http://www.wunderground.com/global/stations/44292. read more
Of several books on the Mongols I have read (Genghis Khan and the Making of the Modern World,The Mongols and the West: 1221-1410), Morgan's history is my first choice. read more