When you want to start beeing a DM, you really should take a deep look into this (and the players handbook). It contains massiv information of the world and how to rule a game for your players. I like the composition. You can skip parts, which are not needed at the moment (like "how to rule a city/Entcounter in City" if you are playing completly in the nature). It is good for understanding the rules of DnD, 5th edition. Oh and the drawings inside are awesome! I really love that!