From the description:
This is a 6-monster bestiary, with instructions on how to remix the 6 into a multitude of creatures for your old-school D&D campaigns. The stat blocks provided easily cover months of low-level play without use of any other bestiary. The instructions supplement other bestiaries well, providing broad, applicable principles for creating your own spins on existing monsters.
ALSO this is a 5-element treasure generator, for when you lack hoards for your monsters and don't want to go through the lengthy process of "official" treasure table usage. Note that this 5-element treasure generator breaks down mathematically for characters of 5th level and above, but even so, it will save you a lot of time and energy for your early campaigning.
ALSO this is a 1-page dungeon about an archaeological dig that has been taken over by cockatrice-taming bandits that shows the utility of the aforementioned bestiary and treasure generator.