In the Good Old Days (TM) shells were introcuced to us by the file
/usr/share/doc/usd/04.csh/paper.ascii.gz
on a FreeBSD machine
(I can put it on atle.linux-site.net if you want to)
If you read it, but you must either put yourself in a 'newbie-ham' (is fun) or skip the things that explain what a shell is and how to do 'ls' - you will understad why we were fascinated by csh.
And you may actually want to know it well enough to be able to deploy on a system where csh is the default shell - you quite often see things like
setup.sh setup.csh
plus a weird shell called batsh or something (setup.bat)