The BBC has a nice article covering the history of the Swiss army knife…
http://news.bbc.co.uk/2/hi/europe/8172917.stm
I’m one of those people who carries a Swiss army knife on his person every day. Mine has several gadgets that I use almost every day including a small LED pen light. For every slot, screw, and hole there is a tool on my knife to work with it. I honestly would have a hard time getting through the day without it.