[Mac only] By default, Mac’s Mail client displays mails in a top-down approach, thus limiting the number of mails it can display, If you are using a widescreen monitor, here’s a Mac plugin that allows you turn the top-down to left-right column view.

This 3 vertical columns view plugin is fairly easy to implement. Just install, and restart your Mac Mail client and your Mail client should now display in three vertical columns.

How to revert back

If somehow you don’t like the 3 column view after some time, launch the Plugin Library, uncheck the Letterbox plugin and restart your Mail Client.