It’s fascinating how valuable simple diaries or letters are to history. Even something like documenting an encounter on a train (not that meeting Einstein is anything small).
They're a ton more valuable than what we think of as "historic documents". We get taught in schools that history comes in the form of direct, straightforward pronouncements -- the kind associated with big events like a revolution or major discovery.
To learn what things actually felt like, and how people actually saw the world, historians end up building up their pictures from a lot of ordinary artifacts. Writings are fantastic if you can get them, especially candid ones like letters and diary entries. They contain the tiny scraps of information about what people do every day.
Garbage dumps are similarly full of valuable information about what people ate, what they considered important, and what they owned. People think of the junk as gone so they don't filter it. It's truthful in a way that their carefully preserved valuables can never be.
The real work of historians is an enormous amount of drudgery, reading vast amounts of dull material and trying to put together a picture from that. It's not exciting, but to the people who do it, they love the vividness and connection they get.
