For those who haven't read it, the book is essentially about how computers work, from first principles up to integrated circuits and high-level programming languages. What makes the book special is the excellent writing: it has an engaging, conversational style, and is accessible to a non-technical audience.
If he's taking more time for himself (and hopefully, to write more books, as indicated in the post), that's awesome.
Code is a great book. I've also been supplementing it with the From Nand 2 Tetris course[1] in order to have some applied experience with the concepts.
http://www.charlespetzold.com/books/#code