Among the many things I've been ingtrigued by, living where I do and playing Dux Britanniarum and other Dark Ages games, is what the landscape actually looked like in the Dark Ages. Peterborough is right on the edge of the fens - witness such places as Flag Fen, and further east, Ely, with its cathedral known as the Ship of the Fens. A lot of this area, and indeed a fair bit of Lincolnshire, was wholly or partially underwater.
Hence, when I spotted a copy of An Atlas of Anglo-Saxon England (which does appear to be somewhat rare) for under £30, I snapped it up.
I have to say, perhaps unsurprisingly, it's not a gripping read, but then this kind of book isn't one you keep around to while away the hours with a ripping yarn! It's actually a little out of period for Dux B, as it starts around 700 AD, but it is though, full of interesting and in some cases fascinating maps. It's clear, for example, from the maps of Lincolnshire's drainage, that I need to build a couple of marsh/fen boards (which I was kind of planning on anyway, but...)
I guess this book comes under 'you'll know if you need a copy'. I find it fascinating.