R.J.
I was diagnosed at 11, but aside from a couple week trial of Ritalin went med & therapy free until I was an adult. But since I don't actually fit your Q I probably shouldn't say more.
One of the best ADHD books on the planet, however, is SPECIFICALLY for adults diagnosed with ADHD. I often reccomend it to parents of kids with ADHD because it looks at things from an adult perspective over time which makes adhd understandable to parents as opposed to a "you should do x with your child blah blah blah" that a lot of books on adhd are. But, as I said, it is the *classic* diagnosed as an adult adhd book. And it's phenomenal.
Here's the book. Try and not throw it across the room as much as I did (SO frustrating to realize how much "better" things could have been if I'd been treated sooner instead of left to my own devices).
http://www.amazon.com/You-Mean-Lazy-Stupid-Crazy/dp/07432...