I started learning kernel internals from these books, I highly recommend all of them. Operating Systems: Three Easy Pieces (free online) - Arpaci-Dusseau Linu

I started learning kernel internals from these books, I highly recommend all of them. Operating Systems: Three Easy Pieces (free online) - Arpaci-Dusseau Linux Device Drivers, 3rd ed (o'Reilly) - Jonathan Corbet The Linux Programming Interface - Michael Kerrisk The Design and Implementation of the FreeBSD Operating System (2nd ed) - McKusick, McKusick, Watson Solaris Internals - McDougall, Richard, Mauro