The last addition to the Core Collection, the Architect, is designed for the Dungeon Master Guide.
Created with all dungeon masters in mind, it contains maps, spells, dice, and coin to give out to deserving players. The D20 with the critical hits in the top and fails in the bottom are a favourite from the old design. And the map in the centre is designed by the amazing Deven Rue.
The cover slips around your own Dungeon Master Guide like a sleeve, and in no way harms your book. In fact, it even protects it so you can keep playing for many years to come.
Find more of Deven Rue's cartography on rueink.com.