The Hollywood Myth of the Horizontal Handgun Grip: Safety and Accuracy

Question
In TV and movies, actors are often shown firing a handgun, holding the grip horizontally.  The actor is almost always firing one-handed.  It has been some years since I took a formal course in handgun shooting.  Is this horizontal technique something new for which I should return to school?  Thank you for sharing your expertise.

Answer
No, this is not a legitimate way to shoot a handgun. It is something Hollywood invented, and which "gangstas" think is cool, which is very good since it this particular grip and stance makes it unlikely that one could hit a target (= intended victim) at more than about three feet distance, except by chance.