This booklet contains random number tables. In this case D12 rolls. There are times as a DM/GM when you want to make a observation check or a skill roll but at the same time you do not necessarily want to alert your players. Maybe you are running a mass battle and you just want to speed things up. Maybe you are not in a position to take out your dice and you need to make a few rolls.
For whatever reason these tables give you the ability to produce random rolls on demand without dice.