klogd(8): man page documenting the klogd kernel logger, including nondefault uses (e.g., diagnostics, etc.).

logger(1): man page documenting the logger utility.

sysklogd(8): man page describing Linux's implementation of syslog and how it interacts with klogd. It also provides a list and description of syslogd's startup options/flags.

syslog.conf(5): man page providing detailed syslog configuration-file syntax, options and use.

syslog-ng Home Page: A next-generation system logger that is much more powerful than syslog.