An early advertisement for VisiCalc. Take a gander at the size of that floppy!

Everyone say “Happy Birthday” and “Thanks!” to Dan Bricklin, born today in 1951. The computer software pioneer co-created the granddaddy of that Excel window you’re pretending to work on right now.

Bricklin and Bob Franklin wrote and coded VisiCalc, the first-ever spreadsheet program for the home computer market. Before the 1979 release, personal computers weren’t seen as necessary for business use, but the spreadsheet, released first for the Apple II and later on for the Commodore Pet, Atari and other systems, struck a chord with offices everywhere especially when they realized they could use the spreadsheet to speed up record-keeping and deduct the considerable expense of the computer in the process. This, of course, was before everyone realized they needed a computer to watch cat videos.

Celebrate today by visiting Bricklin’s site, which has tons of history and info on VisiCalc and the computing industry in general. It’s a fascinating read, so take your time and keep that Excel spreadsheet handy to cover up the screen when the boss walks in.

Photo credit: Flickr/ScriptingNewsTweet