Shortly after Google + launched in 2011, authorship was introduced as a search ranking signal.
Google authorship was originally introduced as a way to connect authors to the content they pushed out, by including a headshot of the author, a byline, the number of times the author has been circled on Google+ and a rich snippet which helps show searchers exactly what kind of information an article contains.
Creating Google Plus authorship is a two-prong approach accomplished by having a completed Google+ profile and adding a code to your website linking the content you push out to your Google+ profile.
Aside from being pretty cool for the author; putting their face front-and-center on Google alongside their content, people have shown they are more likely to click on an article written by a real human (whom most content on the web is written by anyways) with some authors reporting a 30-150% increase in click-through rate on organic search impressions by implementing the authorship tag.
While authorship still exists, its prominence may be coming to an end.