I need to describe the theme of spying in Hamlet by William Shakespeare.
By far the worst offender is Polonius. He is the king's right-hand man, so we assume he has had some practice at it and perhaps some need for it. However, he spies even on his own children. Polonius sends Reynaldo, his servant, to spy on his son, Laertes, while Laertes is away at college. Even worse, he tells Reynaldo that he is free to spread some lies about Laertes as long as they help him discover the truth.
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Let me correct an item from the above post. There are no bedrooms in the play. The scene where Polonius spies on Gertrude and Hamlet is set in Gertrude's closet not her bedroom.
Also, the spy theme is actually part of the larger theme of image and reality. First, spying basically involves an observer and the observed. This is similar to an actor being watched by an audience. Accordingly, the person being spied upon may well be "acting". One of Shakespeare's main themes that cuts across most of Shakespeare's plays is that we all "act" and we all are observers. So during "The Mousetrap" Rosencrantz and Guildenstern are watching Hamlet as is Polonius. At the same time Hamlet and Horatio are watching Claudius and they all are watching the play. Reynaldo as Polonius's spy is supposed to act a certain way. Rosencrantz and Guildenstern are supposed to spy on Hamlet and yet he knows they are spies. Hamlet of course acts crazy. So spying is really just one aspect of a larger continuum.