Check the following books on "The Linux Kernel" at
Kernel book "http://kernelbook.sourceforge.net" and at "http://sourceforge.net/projects/kernelbook"
Linux Kernel books like 'The Linux Kernel Module Programming Guide', 'Linux Kernel 2.4 Internals', 'The Linux System Administrators Guide', 'The Linux Network Administrator's Guide' and others at "http://www.tldp.org/guides.html"
FreeTech books "http://www.tcfb.com/freetechbooks/booklinuxdev.html"
Rusty's "http://www.netfilter.org/unreliable-guides"
Linux Kernel links "http://www.topology.org/soft/lkernel.html"
Linux Kernel Internals "http://www.moses.uklinux.net/patches/lki.html"
Books links "http://linux-mm.org/kernel-links.shtml"
Refer also to other relevant HOWTOs at:
Bootdisk-HOWTO
Sound-HOWTO : sound cards and utilities
SCSI-HOWTO: all about SCSI controllers and devices. And see also SCSI-2.4-HOWTO
NET-2-HOWTO: networking
PPP-HOWTO: PPP networking in particular
PCMCIA-HOWTO: about the drivers for your notebook
ELF-HOWTO: ELF: what it is, converting.. Mirror sites at ELF-HOWTO-mirror . See also GCC-HOWTO
Hardware-HOWTO: overview of supported hardware
Module mini-HOWTO: more on kernel modules
Kerneld mini-HOWTO: about kerneld
BogoMips mini-HOWTO: in case you were wondering