Lyric discussion by miesvanderrobot 

Cover art for Mack the Knife lyrics by Bobby Darin

This song is from Brecht & Weill's Threepenny Opera, which was itself based on the Beggar's Opera by John Gay. In the Brecht version, Macheath (aka Mack the Knife aka Mackie Messer) is absolutely ruthless. The whole Threepenny Opera is a scathing critique of capitalism, and the song itself is bloody and filled with tales of arson, rape, and murder (sanitized considerably in the most well-known English translation which we know and love). Don't let me catch you playing this at your wedding because no matter what famous crooner sang it, it is not romantic, and it is not appropriate for an insanely expensive party. Brecht would roll over in his grave.

Here are a few sample stanzas from a more faithful translation of the original German (tr. Manheim & Willett):

And the ghastly fire in Soho,
Seven children at a go—
In the crowd stands Mack the knife, but
He's not asked and doesn't know.

And the child bride in her nightie,
Whose assailant's still at large
Violated in her slumbers—
Mackie how much did you charge?

For everything you ever wanted to know about this song, just search the Internet for "Everything you ever wanted to know about Mack the Knife"...you'll learn a lot.