Roger McDonald's Mr. Darwin's Shooter caught my eye in the stacks at the shop a few weeks ago, and I've been slowly reading it bit by bit on the T since then. It's quite a nice piece of historical fiction, highlighting the little-known character Syms Covington. Darwin's erstwhile assistant on the Beagle voyage and longtime correspondent thereafter, Covington is an enigmatic character, who left a narrow paper trail (online here) and more than a few mysteries.
McDonald's narrative takes place in two time periods: one plot-line follows Covington through his early years and along with Darwin on his travels, while the second portrays him as an aging man in Australia awaiting the arrival of Darwin's On the Origin of Species. This device is put to excellent use here; it allows McDonald to introduce a welcome element of suspense and curiosity into the excellently-written narrative.
The tensions in this book are the tensions that have always followed Darwin: as a man of great religious conviction Covington, is profoundly troubled at the conclusions to which his observations lead him (before, it is suggested, they led Darwin to the same place). McDonald handles these tensions well, and has fashioned from them a very good book.