One book I've been saving for a while, and didn't quite get round to starting, was Mike Stocks' White Man Falling. If I'd finished the McGregor book quicker I would, but I got sidetracked after reading the Twain biography into finding out more about the aftermath of the American Civil War. It's an exciting life I lead.
Over the weekend, though, it got an appreciative review in either the Daily or Sunday Telegraph (can't remember which, or find it online), so I'll save it for a long train journey (always my favourite place to read).
Mike is the editor of excellent pocket-sized, anonymous submissions poetry mag Anon. I'm not sure if it's on hold at the moment, but the back issues are worth a look.