Also, the Circardian Code by Satchin Panda.

I have read both recently, and there is a lot of overlap, but the Circardian Code goes beyond sleep into nutrition and execise, as well.

Oh yes, definitely. Another one from these experts is Valter Longo with his book "The Longevity Diet". All three of them were interviewed by Rhonda Patrick https://www.youtube.com/user/FoundMyFitness/videos for people who like to watch/listen before reading. Matthew was also a guest in Joe Rogan Experience https://www.youtube.com/watch?v=pwaWilO_Pig

I found only one point in which Satchin Panda and Matthew Walker were disagreeing:

Satchin said that there were no (genetic) sleep types among humans (who prefer to get up and go to bed early, or late) referencing a paper in which a group of students went on a hiking and camping trip where they all synchronized to the same rhythm after a few days of exposure to all natural light.

Matthew, on the other hand, says that there are definitely variations in sleep time preference in humans, with a genetic base and recommends to find out so that the ideal time windows for work and sleeps are chosen. Does not give a reference, sadly.

Not sure what to make of it, really.

Hahaha, I know this book will show up soon or later. I haven't finished the book yet. But the book is very informative and easy enough to be read.

Currently reading this at the minute. Extremely easy to read and informative.