What's a good hook for an introduction to an essay on the theme of authority in the book The Crucible?

Often, an interesting way to go with a hook is to begin your essay with an attention-grabbing quotation that relates to and sheds light on your topic.  This way, in your introduction, you can begin to discuss the importance of your topic, and the quotation will also give you a way to close your essay.  In your conclusion, you can return to the quotation and discuss it in light of all you've argued thus far. 

Here are a couple of ideas:

"Authority, when first detecting chaos at its heels, will entertain the vilest schemes to save its orderly facade."  - Alan Moore, V for Vendetta
This quotation definitely relates to Reverend Parris's behavior throughout the majority of the text, as he is so desperate to hold on to his authority and position that he actually withholds very important information from both Reverend Hale and the court.  He maintains silence in order not to cast doubt on his own house -- since it was his niece and daughter who were dancing in the woods, conjuring spirits -- and his silence, in part, allows the trials to begin and to go on for as long as they do.  You could also relate this quotation to Deputy Governor Danforth's behavior and priorities in Act Four, once it has become clear, even to Parris, that the trials have been corrupt.

"Authority without wisdom is like a heavy axe without an edge, fitter to bruise than polish." -- Anne Bradstreet, a Puritan poet, living in the colony
Such a quotation would also very much relate to the way in which authority is wielded in The Crucible.  Neither Parris nor Hale (at least, initially) nor Danforth nor Hathorne seems to possess and/or exercise wisdom in their positions of authority.  Danforth seems to employ a thoughtless logic (either one is with his court or against it), Hathorne only wants to demonstrate his ability to convict so that he can be promoted, and Parris only desires to strengthen his position in the face of the faction he believes wants to undermine him.  By the end of the play, their wisdom-less authority has taken a heavy toll, more than "bruising" Salem; "destroying" would be a more accurate term.