From an article on The Sociopathic Style™:
A sociopathic person is walled off from their inner core. How they present themselves to the world is a facade. Their operational system is power. To relate to them by playing the power game is a losing proposition because they are masters of the game and they will win at all cost.
The Mask of Sanity: An Attempt
to Clarify Some Issues About the
So-Called Psychopathic Personality
is a book by American psychiatrist Hervey M. Cleckley, first published in 1941. It is considered a seminal work and the most influential clinical description of psychopathy in the twentieth century.
Cleckley, a pioneer in psychopathy research, coined the phrase mask of sanity to describe the psychopath’s ability to perfectly mimic a normally functioning person and to mask or disguise the disorder; a fundamental lack of moral conscience and internal personality structure. Despite the seemingly sincere, intelligent, even charming external presentation, internally the psychopathic person does not have the ability to experience genuine emotions.
Psychopath Resistance 