Somebody left a copy of Candice Millard's book River of Doubt in the truck my sister gave me, and I just finished reading it. It's about a river trip Teddy Roosevelt took after he lost the 1912 election, in which he mapped a previously unknown 1,000-mile long tributary of the Amazon. I am not a huge fan of TR (he seems to be a really big fan of war) but I appreciate the fact that he was a tough dude. Like pretty much every adventure narrative, it diverges from the main story to describe the science or history behind the obstacles the adventure faces, but it does so in a slightly repetitive manner. The Amazon has lots of crazy insects. I get it.
Anyway, I'd say the book is above average adventure narrative, but not amazing. It was interesting to read about a politician doing some serious adventuring, and it was interesting to learn something completely new about somebody you've obviously been hearing about (but for different reasons) your whole life.