Continuing Education Book Bleg

Back in the heady days of the beginning of this fiscal year (my company's fiscal year runs offset from the calendar year), when I as filling out my annual performance plan, I added a section for "personal and professional development" in which to assign myself to read books. Last year, I'd done this without authorization, and so the assignments were designed to fit my existing reading habits:

At least one book each from each of the following categories:
1) Literature
2) History
3) Philosophy or Theology
4) Science
5) Economics or Mathematics

This year, when I queued up the same performance plan item again, my boss sent it back with the advice that I try to be a bit more "relevant", with the result that I ended up with:

At least one book each from each of the following categories:
1) Economics
2) Mathematics or Statistics
3) Leadership

However, I'm promptly forgot about this less self-indulgent assignment, and so as I near the end of the fiscal year I realize that I've only hit the first of the three.

So, in the interest of not having to give myself a poor assessment on a strictly voluntary performance plan item (though given the show-off-ish nature of the assignment, perhaps it's no more than I deserve) I ask our knowing readers: Do you have any books you would particularly recommend which I could make the case fit 2) or 3)? These certainly don't have to be textbooks, and I'm prepared to make a creative case that something fits one of the requirements. (For instance, I've contemplated reading Machiavelli's The Prince again in order to cover "Leadership", if a better idea doesn't come along.)

Thoughts?