Use a spell, without assigning it to right click?

I recently acquired the spell Identify in torchlight, and I use it from within my inventory by right clicking the icon. This works fine, except that it overwrites my current right click ability with Identify. Is there a way I can use a spell directly in inventory without it overwriting my currently selected right click ability?

You can assign anything to hotkeys: click any of the hotbar slots and select the spell or scroll:

Now, when you press the number assigned to the hotbar slot (in this case, 7), it'll cast the spell.

Assigning skills and spells to your right button isn't too bad if you know that there are shortcuts to assigning them. I imagine you didn't want to assign it because you think you would have to click through the different menus just to pick a different one. It's not as bad as you think.

You can assign non-passive skills (i.e., skills that aren't "always on") to your right button using the F keys (i.e., F1, F2, F3, etc.). Just hover over an skill and press the desired F key. Pressing it again will make it your active skill. This will give you quick access to your skills and spells that you don't necessarily need all the time while leaving your quick slots open for the important ones and your inventory.

For some pointers, I'd assign all your "attacking" skills (e.g., fireball, ricochet, devastate, etc.) and others that you can afford not having immediate access to (e.g., identify, town portal, etc.) to your F keys and everything else that you need immediate access to in battle (e.g., potions, auras, summons, etc.) or whatever is convenient to your number keys. This way, you can keep your options open when you are in battle while having others accessible when you're not.