Can someone explain Book 2: Chapter 9? And the significance of room 101?A summary of what is contained in Goldstein's book would be very helpful.
Even though your question is stated simply, you are touching on some of the most complex aspects of the novel. Goldstein's book explains, among other things, the political and economic system of the three remaining superpowers that keeps their respective societies under totalitarian control.
Winston reads skips to the third chapter, for instance, and reads "War is Peace." Here we find that by keeping populations and a perpetual state of stress and need they become passive and compliant. War, or at least the notion of war, uses up surplus goods and gives the people an outlet for their stress and hatred. They will never have enough goods to truly satisfy themselves--because then, of course, people would want to start solving other problems, namely dissatisfaction with the government. And they will continually hate an outside force, never turning their attention to their own government.
Your question attempts to connect Goldstein's book in this chapter to Room 101. Utlimately, the connection is fear. People can be controlled only if they are in a state of fear. The Book speaks mostly in terms of whole populations and governments, but Orwell shows that the same concepts are true for individuals. Whatever is in Room 101 is your greatest fear--the thing that will break you. This is the ultimate symbol of power and control.
For a great explanation of specific details in Book 2, Chapter 9 you should visit http://www.enotes.com/1984/summary