Have the person making said skill book pay in inspiration proportional to the requirements to learn said skill, have proficiency required to essentially re-learn said skill, and some rare materials in construction of the skill book, or something along those lines.
Person reading the book needs to pay in a certain amount of inspiration, possibly some form of relevant silver sink(admission to education facility in Prov, given that you have a skill book), and various rare inspirationals relevant to the skill being learned from the book.
If the educational facility is implemented, a time delay from consuming book to actually learning the skill could be added(1-7days proportional to difficulty of the skill).
This could allow a fairly new pilgrim to learn a skill such as cotton planting before he/she has access to said skill via traditional means. Obviously pursuing the skill via traditional means has benefits in terms of production efficiency skills learned along the way, the bonus of +plenty through stocks & cultivares etc.
Skill books should only be available for civilian skills to avoid abuse of things like thieving and the like. Basic combat skills like fencing shouldn't be a problem though.
Skill books, along with the required inspirationals, could also be added to the store packs as an additional incentive to provide funding to the development of the game.
There are many variables available to balance this addition to the game.
Thoughts?