
Nothing too fancy, this is basically a free Working a Hunch with the added option of creating a clue out of thin air, which is a fairly unique ability for a card. It might allow you to avoid a hard-to-access location while still finishing the act. It could also turn back on Fieldwork or Inquiring Mind or any other card that requires a clue on a location. If you are a bad person, it could cancel a VP location for your team. Most interesting, maybe, is that it can serve as a safety net for Roland's "box" set signature weakness if you draw that late enough in the game that there are no locations with clues. This makes Roland the only investigator with a clear synergy between his "box" and "book" signature sets.
So, if you are risk averse, play the "book" set. If you aren't, consider playing both.
On edit, that should read "clear positive synergy." When one weakness helps you with another, that's amore.