Windows 8.1 removed Libraries from the navigation pane in explorer. Here is how to get it back.
(note – This guide will become part of the upcoming revision of Tweaking Windows 8)
Default view without Libraries.
The Navigation Pane is the section on the left side with Favorites, Desktop, etc.

To get Libraries back:
Click View > Options

Check the Show libraries box > click Apply

The Libraries are back.

I like this option better:
Check the Show all folders box

Adds Libraries + User folder + Control Panel + Recycle Bin to navigation pane.

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