Nonfiction Reading Challenge Sign Up

I was actually hoping for a nonfiction reading challenge to sign up for but didn't notice any before this - or the ones I did notice had too many categories.  Anyway, I'm signing up for Seeker Level (11-15) since that should hopefully encourage me to read at least one a month.

Nonfiction books read so far:

1. Hitler's Furies by Wendy Lower
2. The Consolation of Philosophy by Boethius
3. Paris 1919 by Margaret MacMillan
4. The Second Treatise of Government by John Locke
5. A Discourse on Inequality by Jean-Jacques Rousseau
6. Karl Marx: A Life by Francis Wheen
7. The Book of My Lives by Aleksandar Hemon
8. I Don't Know What You Know Me From by Judy Greer
9. Son of a Gun by Justin St. Germain
10. This Boy's Life by Tobias Wolff
11. The Prince by Niccolo Machiavelli
12. Brain on Fire by Susannah Cahalan