Other people's letters
I've been reading up on Darwin for a bit of consultancy work I'm doing this summer (everyone's about to go Darwin-loopy next year, there are eleven exhibitions planned for Cambridge alone...). As part of this work, I've been spending time on the Darwin Correspondence Project, and I wanted to recommend it simply as a surprisingly interesting site to surf-through.
Darwin was a great letter writer. By the 1870s, he was writing 1500 a year. They helped him extend his network of supporters, but it also increased the reach of his observations on nature. He has all sorts of people collecting information for him - pigeon fanciers, barnacle aficionados (yes, really).
The letters on the correspondence site are incredibly absorbing. I thought it would be all just dry archiving, useful for the geekier historians of science, but its so much more than that. Maybe I'm just being nosy - sneaking a read into other peoples letters - or maybe I'm more of a geeky historian of science than I admit. Judge for yourself, it's all online.