What a piece of work is a man
The speech 
The monologue, spoken in the play by Prince Hamlet to Rosencrantz and Guildenstern, follows in its entirety; rather than appearing in blank verse, the typical mode of composition of Shakespeare's plays, the speech appears in straight prose:
I will tell you why; so shall my anticipation
—The Tragedy of Hamlet, Prince of Denmark (Act II, Scene ii, 285-300), 
Differences between Folio and Quarto texts 
|“||What a piece of work is a man, how noble in reason,
how infinite in faculties, in form and moving,
how express and admirable in action, how like an angel in apprehension,
how like a god!
J. Dover Wilson, in his notes in the New Shakespeare edition, observed that the Folio text "involves two grave difficulties", namely that according to Elizabethan thought angels could apprehend but not act, making "in action how like an angel" nonsensical, and that "express" (which as an adjective means "direct and purposive") makes sense applied to "action", but goes very awkwardly with "form and moving".
Scholars have pointed out this section's similarities to lines written by Montaigne:
|“||Qui luy a persuadé que ce branle admirable de la voute celeste, la lumiere eternelle de ces flambeaux roulans si fierement sur sa teste, les mouvemens espouventables de ceste mer infinie, soyent establis et se continuent tant de siecles, pour sa commodité et pour son service ? Est-il possible de rien imaginer si ridicule, que ceste miserable et chetive creature, qui n’est pas seulement maistresse de soy, exposée aux offences de toutes choses, se die maistresse et emperiere de l’univers?
Who have persuaded [man] that this admirable moving of heavens vaults, that the eternal light of these lampes so fiercely rowling over his head, that the horror-moving and continuall motion of this infinite vaste ocean were established, and continue so many ages for his commoditie and service? Is it possible to imagine so ridiculous as this miserable and wretched creature, which is not so much as master of himselfe, exposed and subject to offences of all things, and yet dareth call himself Master and Emperor.
However, rather than being a direct influence on Shakespeare, Montaigne may have merely been reacting to the same general atmosphere of the time, making the source of these lines one of context rather than direct influence.
References in later works of fiction and music 
In the Reduced Shakespeare Company's production The Complete Works of William Shakespeare (abridged), the more famous solliloquy, "To be, or not to be," is omitted from the Hamlet portion of the production, not for time constraints, or because the speech is so well known, but because the group states that they dislike the speech for momentum and motivation reasons. The "What a piece of work is a man" speech is delivered in its stead.
- In Bruce Robinson's 1986 British film Withnail & I, the credits roll after lead character Withnail recites the monologue to an audience of wolves in London Zoo.
- In the film Grosse Pointe Blank, Mr. Newberry says to Martin: "What a piece of work is man! How noble... oh, fuck it, let's have a drink and forget the whole damn thing."
- An episode of the television show Babylon 5 aptly named "The Paragon of Animals", had one of the characters, Byron, recite Hamlet's "how noble is man..." speech.
- In the Star Trek: The Next Generation episode “Hide and Q” Captain Jean-Luc Picard says to “Q”: "I know Hamlet. And what he might say with irony I say with conviction: ‘What a piece of work is man! How noble in reason, how infinite in faculty, in form and moving how express and admirable, in action how like an angel, in apprehension how like a god!’ ” (II.ii.304-308).
- In Gettysburg (1993), Union Colonel Joshua Lawrence Chamberlain recites from the speech while discussing slavery. To which Sergeant Kilrain responds "Well, if he's an angel, all right then... But he damn well must be a killer angel."
- In the rock musical Hair, numerous lyrics are derived from Hamlet, most notably a song titled "What a Piece of Work is Man", which uses much of the speech verbatim.
- In the 2009 Henry Selick film Coraline, two trapeze artists quote this speech during their performance.
- In the 1982 Ridley Scott film Blade Runner, Rutger Hauer said he was inspired by this speech when preparing for the "Time to Die" scene.
- In the 1982 Lindsay Anderson film Britannia Hospital the computer which is the outcome of Professor Millar's Genesis project recites "what a piece of Work is a Man" up to "how like a God", at which point it repeats the line over and over.
- In the 1986 film Down and Out in Beverly Hills, Jerry Baskin recites this speech on the pier.
- Shakespeare, William. The Globe illustrated Shakespeare. The complete works, annotated, Deluxe Edition, (1986). Hamlet, Act II, scene 2, page 1879. Greenwich House, Inc. a division of Arlington House, Inc. distributed by Crown Publishers, Inc., 225 Park Avenue South, New York, NY 10003, USA.
- The New Shakespeare: Hamlet. Cambridge University Press, 1968.
- Knowles, Ronald. "Hamlet and Counter-Humanism." Renaissance Quarterly 52.4 (1999): 1046-69.