Hamlet is a Shakesperean tragedy about a young prince named Hamlet who is tasked by his dead father, also Hamlet, to avenge his murder by Young Hamlet's uncle (and Old Hamlet's brother), Claudius. 

 The story is not original to Shakespeare. In fact, it was a well-known story at the time the play was written, with the story dating to the 7th or 8th century. The story takes place in Denmark in that time period, which leads to some interesting quirks (like Denmark's place as a world power, which is a laughable concept now!)      

The play is considered the work that caused Shakespeare and his play company to take off during his lifetime. Since then, has been reproduced and adapted many times, including a 4-hour long movie reading the script verbatim made in 1996. Even 400 years later, the play has still left a huge cultural impact, including everyday phrases, like "a method to the madness."

"To be or not to be; that is the question," arguably Shakespeare's (and theater's in general) most famous line, can be found in Hamlet's Act III monologue