Where do I go for backup info?

I am a new admin, from helpdesk background (quickly learning they are two different worlds), and I find myself at a loss to find “The Basics” on backup. There are a lot opinions on software and hardware, but no real info on the why and how’s. Frommy perspective, backups are just done, that’s how it is, but I now need to convince the President and CEO of my company that we need to do this. I know this must sound naive, but, is there any real definitve books, sites or other materials that cover this? Any suggestions?