Your Inventory is where you manage all the sweet loot you find in Borderlands 2. You'll probably be looking at this thing a lot. The main panel shows your currently equipped items and all the other junk you're carrying around in your Backpack.

Highlight items by just moving your mouse cursor over them. Clicking and dragging an item allows you to compare it with other items and even switch items out just by dropping them where you want them to go. If an item’s just terrible, drop it by pressing Q. You can also sort through your backpack by pressing Pg Up or Pg Dn, and get a closer look at any item by highlighting it and pressing F.