Ok this may be lamer than yesterday's choice but my fav non-fiction is a motivational book called "Who moved my Cheese."
Who Moved My Cheese? An Amazing Way to Deal with Change in Your Work and in Your Life, published in 1998, is a motivational book by Spencer Johnson written in the style of a parable or business fable. It describes change in one's work and life, and four typical reactions to said change by two mice and two "littlepeople", during their hunt for cheese. A New York Times business bestseller since release, Who Moved My Cheese? remained on the list for almost five years and spent over 200 weeks on Publishers Weekly's hardcover nonfiction list. (source)
Anyway I read it a long time ago and really really liked it. That is all.