V is for Viola, an X Window sensation
It gave the Web a Back button -- a wondrous
It's hard to believe now, but it took more than a year for Web browsers to include a go-back button. In the early days, if you wanted to take a step back you had to hope the page you were on had a link to the page you'd just been on, or type in the URL by hand.
That changed in 1992 when a UC Berkeley graduate student named Pei-Yuan Wei heard about Tim Berners-Lee's World Wide Web idea. Wei had developed a hyperlink browser, based on the Mac program HyperCard, to track his own research on Berkeley’s campus-networked Unix X Window platform. He adapted Viola into a Web browser called ViolaWWW and released it to the world in March '92. (Shown here: v3.7 from 1993.)