Good, yet very challenging college level books to read?

Good, yet very challenging college level books to read?
I’m currently an undergrad business student at a top 25 business school and I plan on going on to graduate school, either getting an MBA or Law Degree. I’m a very very good writer and a very good reader. What are some good, yet very challenging books, genres, authors etc. that I can read right now to “passively” prepare or increase my critical thinking and logic skills for the GMAT or LSAT (mostly LSAT)?

An example of a recent book I read for a class is That Noble Dream: The ‘Objectivity Question’ and the American Historical Profession by Peter Novick. It wasn’t extremely interesting to me but it challenged me (in a good way) and I ended up writing a killer essay on it. Please don’t limit your recomendations to this genre or type of book, but that an example.

if you want to do well on the LSATs or GMATs, you ought to be improving your critical thinking and logic skills, you are absolutely right about that. to do this, you ought to be reading philosophical literature, especially early modern. Plato, Aristotle, Kant are all examples of philosophers that (by reading their writings) you will gain substantial skill in analyzing arguments and understanding and developing your logical skills. I strongly recommend reading Kierkegaard, Peter Singer (very modern and interesting), and ESPECIALLY John Stuart Mill’s “On Liberty”.
If you want to take it a step further, read Noam Chomsky, Descartes (“Meditations” – focussed on how we can really KNOW something), and Tolstoy (who has great logical writings as well as novels)
I promise you that all these books and authors will help you change your way of thinking to the type of thinking necessary for successful standardized test scores.
Additionally, just a note (I tell everyone this about the LSATs) – if you’re going to write the LSATs by the Logic Bibles – they will help you SUBSTANTIALLY.