View all the letters of Vincent Van Gogh

Seconded. I'm not much of a nostalgic, but there are some very cool pieces that capture emotions from important parts of history. Some hilariously funny ones and good business ones too.

Most of what is known about Van Gogh (that can't be known from his works themselves) is known from his letters.

Do we know if he explicitly gave permission for his papers to be published?

You were at 0 and I reflexively downvoted you to -1, but now I regret it - I voted a little quicker than thinking.

Upon reflection, I think this is actually an interesting point and would you care to elaborate? I love reading letters from important scientists and statesmen of old, but maybe there is some merit in respecting people's privacy even after they pass on. I'll think on this some, if you have any examples or further thought on the matter I'd be quite interested in hearing it.