I have my eye on Why We Sleep and want to read it soon. I did ask Matthew Walker once about the fact that he says you cannot pay of Sleep Debt whereas William Dement (Promise of Sleep) says you can pay off up to 1-2 weeks but no more. In my experience, I can pay off some sleep debt in a week but it levels out after that.

I haven't heard back on that, probably should message him outside of Twitter, but was hoping for a public dialogue.

https://twitter.com/ElijahLynn/status/922599108950368256