This'll be a short post because it's a pretty simple subject. Players love free experience points. Storytellers sometimes need to encourage players to read longer handouts or characters to do more research and read more books. Why not combine the two needs and provide a cost break on a certain skill for certain research options? I saw this while researching how to best run Masks of Nyarlathotep where someone listed all of Elias Jackson's authored works and mentioned that reading each one allowed the character to tick off a skill as though it had been used in the game (which is the BRP system's version of leveling your character). Different books also ticked off different skills which is a great way to get your player to read the various works and choose which one to study first as they only have so much downtime (time between sessions) in which to do it. So yeah, there you go.
Told you it would be a short post.
NB: I believe the list of books plus tickable skills was in the Masks of Nyarlathotep Companion but I don't have access to my .pdf at the moment as I'm still in the midst of moving. Feel free to correct me in the Comments box below.