A very nice take on how to introduce investigations and mysteries to FIST. The list of training available allows your character to have another layer of uniqueness and usefulness in particular situations.
Having a list of possible explanations for how a character can succeed in investigations not covered by its training is a useful add-in, as well as advice on how to treat an investigation as a GM.
It seems to be as much an interesting expansion to FIST as a good manual on how to make good investigation scenarios.