I recently got an email from Jeff Shrager, who said he'd been working hard to solve a mystery about some famous code.

Eliza, the chatbot, was built in 1964, and she didn't answer questions like Alexa or Siri. She asked questions. She was a therapist chatbot and quickly became famous after being described in a 1964 paper. 

But here is the mystery. We're not sure how the original version worked. Joseph Weizenbaum never released the code. But Jeff tracked it down, and some of the things we thought we knew about Eliza turned out to be wrong.