What did I learn and how?

I JUST finished reading 220 books over eight months (roughly a book a day) in preparation for my History PhD Qualifying Exams, and now I am asking myself, beyond the content, what did I learn from it?

Firstly, I learned that if you know how to structure and defend an argument, you can write a book. There is no deeper trick to successfully creating a non-fiction book. Of course, the magic and artistry of a beautiful book and elegant theoretical proposition remain more mysterious than that, but though not everyone may be able to write a masterful book, many more of us are capable of writing a non-fiction book than we realize.