Three classic books about cults and mind control which are a very good place to start. It helps to begin to understand that we are not alone or unusual:

Captive Hearts, Captive Minds : Freedom and Recovery from Cults and Other Abusive Relationships
by Madeleine Landau Tobias, Janja Lalich and Michael Langone
Combating Cult Mind Control by Steve Hassan
Cults in Our Midst by Margaret Thaler Singer
Books that many of us have found useful:

Call No Man Master by Joyce Collin-Smith
    This is an amazing book by Rodney Collin’ sister-in-law about her experiences on the spiritual
    path with Rodney Collin and others.

The Harmonious Circle: The Lives and Work of G.I. Gurdjieff, P.D.  Ouspensky and their Followers
    by James Webb     It is very helpful to put Gurdjieff, Ouspensky, Dr. Nicoll, etc. into an historical
    perspective and to begin to understand how Gurdjieff and Ouspensky practiced the work and
    how those practices are different from the "work" that is practiced in Sharon's "school."
Taking with the Left Hand by William Patrick Patterson
    Some of the early history about Alex Horn and others.
Rogue Messiahs: Tales of Self-Proclaimed Saviors by Colin Wilson
    Madame Blavatsky and others.
Boyhood with Gurdjieff by Fritz Peters
    First hand account of life with Mr. Gurdjieff at Fountainbleu
My Father's Guru by Jeffrey Mousaieff Masson
    An account of growing up with Paul Brunton (another "guru").
The Sociopath Next Door by Martha Stout
Gurdjieff by Louis Pauwels
Morning of the Magicians by Jacques Bergier and Louis Pauwels
Mistakes Were Made (but not by me), Why We Justify Foolish Beliefs, Bad Decisions and
    Hurtful Acts
  by Carol Tavris and Elliot Aronson
Tales for the Son of My Unborn Child  by Thomas Farber
    Stories about Berkeley, California in the 1960's.
    There is an excellent chapter about the author's encounter with Alex Horn and his "school."

People only see what they are prepared to see.                Ralph Waldo Emerson
Did you ever wonder why only certain books were permitted to be read in school?  Having to ask permission to read a certain book is called censorship. Are you not capable of making up your own mind about what to read and what to believe?  Were you told never to read first hand accounts by Gurdjieff's and Ouspensky's students because your teachers were afraid you would find out how differently other Teachers treated their students? 
Do you have any idea how their schools actually operated?