The following link has been going around on Facebook, especially in some of the groups that I currently belong to:

Gaslighting: What it is and how to know if you are a victim of it.

I'd never heard of gaslighting until the past few months and even then I wasn't sure what it meant.  At a very high level, it is a form of mental abuse, manipulation, and control that centers around someone trying to control the way others perceive them and reality in general.  This article does a fairly good job of explaining it, so I will just let you read it.