I always wondered that why Bloggers never draws it's attention towards multi authored blogger blogs. And it's true that blogger was not having about author section in it's default blogs but now blogger has brought this feature in all of it's default templates.
I've already written a tutorial on how to add this widget in your blogger sites.
Before proceeding to this tutorial you must know that that this widget is linked to your Google+ id and it fetch out the description part and name of the author from your Google+ profile. Therefore this widget is very handy, because you don't need to do much of coding and and writing in your HTML editor. (may be beginners would be happy to listen this)
Screenshot of this widget looks something like this
Let's Start Implementing
Before implementing it you need to read the first tutorial otherwise there are the chances of making mistakes while implementing it. After you have read the posts open Blogger Dashboard → Template → HTML Editor then search for <div class='post-footer'>
After that paste the below given code after it
So you've successfully added the HTML stuff, okay now in this step we'll customize it using CSS.
You need to find this code in your blogger template by pressing Ctrl+F ]]></b:skin>. Now paste the below given code just before it.
After successfully pasting the code save your template and you're done. So this was the simple thing made special using CSS.