A firearm has a frame, a slide mounted to the frame, a trigger, a hammer-type firing mechanism including a hammer, and a manual slide and hammer lock safety mechanism ("manual safety") including a detent spring biased rotatable tab mounted to the frame that blocks the slide from reciprocating and the hammer from rotating relative to the frame if the tab is actuated in an "on" position. The manual safety completely disables the firearm even if the trigger is actuated, thereby rendering the firearm safer.