I came across this this site/blog during my casual browsing.
Some of the articles are interesting and neatly explained with clear
diagrams/pictures.
The author, I heard is also writing a Linux Kernel Internals book(I
believe, he is planning to release it free) which would be released
later(he is not sure when it would be).
But I am expecting the book would be very useful.
Meanwhile, browse through the articles and lot of them are useful and
interesting.
http://duartes.org/gustavo/blog/archives/
Another similar book related to Kernel Internals(but based on old kernel -
mostly still relevant and useful),
"The Art of Linux Kernel Design: Illustrating the Operating System Design
Principle and Implementation".
note: I do not know the author(s) personally or there is no
benefit/business motive in this.
thanks
carti