In the annals of scholarly research, it is possible that nobody in history has been written about more than Adolf Hitler.

By 1975, 30 years after he killed himself at the end of World War II, more than 50,000 books and scholarly articles had been written about him, according to a 2006 study of those studies. Two decades later, the total reached 120,000.

“That computes to more than 24 scholarly books and articles on Hitler and Nazism published every working day for 20 years — and the number is growing exponentially,” the study said. “Thus public interest in the mystery of Hitler continues to grow, with no end in sight.”

Yet among these millions (probably billions) of words, relatively few have illuminated the lives of two central figures in Hitler’s life — his parents Alois and Klara, about whom little-to-no primary research materials survived the world wars.

Or at least that’s what historians had resigned themselves to accepting.

But one of the tropes of history are letters that turn up in dusty attics. And a few years ago, in the tiny Austrian town of Wallern, a pensioner named Anneliese Smigielski was rummaging in her attic when she happened upon 31 letters written by none other than Alois Hitler.

Jackpot.