I’ve been getting into reading more biographies, and for the most part, it’s been great, but there’s always a lingering thought in my head asking: how much of this is real? I remember large phases of my life, and I get that a biographer would interview people around them/take countless hours trying to remember the past, but how can you remember so many things in such great detail?
A lot of biographers pore over their subjects’ correspondence, and lots of people, at least until recently, saved every letter they ever got (this made business sense, since letters could be used as legal documents). So you could often get a good day-to-day record of their lives that way.
Now multiply that by all the people who corresponded with them, and the amount of data goes up rapidly.