Handguns were invented as a way to have a small portable gun (as opposed to a rifle) that was easy to keep on your person for defense.
Yes, handguns were used in WWI, and WWII.
That's a very difficult question to answer because, of course, any caliber can kill. Smaller caliber handguns are fairly common in crime involving handguns because people believe large handguns are too diffucult to conceal. Most major police agencies in the U.S. use 9mm or .40 caliber handguns. It's also difficult to answer because information on caliber used in homicide and other crimes isn't readily available.
tools of the trade
Self defense, collecting, shooting.
There were single shot pistols and revolvers.
No use of handguns? that would be my best guess
No one source of information.
In this order; centerfire rifle, shotgun, handguns.
Yes, handguns have a serial number.
First used at the battle of Ain Jalut in 1260 by the Mamluks.
that particular category of death is not tracked.
Killing people, the same as any other era's handguns.