Just added a set of books, a spawn grouping (I think it works?) and a practice recipe for learning the profs. c: Enjoy
Also, as nice as the vanilla engines for helicopters are, they consume way too much fuel as of now so I highly reccomend replacing them all with a dual diesel/electric engine setup with a load of batteries. Should give more than 3 minutes of flying time that way.
The books have a pretty low chance of spawning in lab_bookshelves, military_book, and hardware_book, just to gate them a bit, they also sell for quite a bit just to reinforce how valuable the information they provide is and to reflect the rarity, Hopefully it doesn't break traders, if so I'll adjust it as I play through with it installed.
Do know that reading the book itself doesnt teach the profs, you have to "practice" them to learn the profs ala studying the books, which should take about 20 hours each. There should be two recipes with the books when you first read them, as well they function as mid level mechanics books.