Magnum opus

Magnum opus, from the Latin meaning great work, refers to the best or most renowned achievement of an author, artist, or composer.

Examples:

• da Vincis' Mona Lisa (La Gioconda)
• Thomas Kuhn's The Structure of Scientific Revolutions
• Händel's The Messiah
• Goethe's Faust
• James Joyce's Ulysses
• John Philip Sousa's Stars and Stripes Forever