Some of you might be thinking of buying a first ever firearm and that be a pistol............. Here's a bit of the info you might need.
All firearms up to around 1880 or thereabouts used black powder; modern firearms use smokeless powder, which is much more powerful. About 50% of black powder turned into smoke and grime, the other half into expanding gases to propel a bullet forward; modern smokeless powder is more like 99% or more turning into gases to propel the bullet.
The big pistol cartridges you see in revolvers arose in the black powder age. They killed people then; fill one of them with modern powder and a bullet in front of it, and you have a gun for killing tyrannosaurs and giant space aliens.
The much smaller cartridges for modern semiauto pistols arose in the smokeless powder age and are totally adequate for any normal purpose.
Cops often prefer revolvers and some people prefer revolvers for home defense because they are simpler and relatively more foolproof. They only have the five or six shots however; reloading is time consuming.
Semiautos to my thinking are more than reliable enough if you use them properly, can hold more than twice as many shots, and can be reloaded by simply pulling one magazine out and popping another in. That was the original idea.
There's another big consideration about semiauto pistols which most people miss, i.e. how do they work and to what extent does that affect accuracy. Above a certain level of size, most semiauto pistols use the locking system which John Browning invented for the US Army 45 and that does impact accuracy somewhat. Without that, i.e. in order to have a 45 semiauto and a simple blowback mechanism, you'd need a spring so heavy that most people would not be able to cock the pistol.
What I recommend would be the largest semiauto you could buy with a fixed barrel and a simple blowback mechanism, which is going to be a 380 or, possibly, one of those slightly more exotic pistols which Beretta and Taurus make which use 9mm ammo with a fixed barrel and an exotic locking system.
Normally that would mean to buy some sort of a decent 380 on gunbroker.com or at some gunshow, and then find the heaviest ammo I could for it and fire a couple of hundred rounds with it to make totally certain that it never jams or fails to operate with that ammo.