Tschaikowsky's 'The Nutcracker' is a two-act ballet on a libretto adapted from E. T. A. Hoffmann's story 'The Nutcracker and the Mouse King'. It has become one of his most famous compositions, in particular the pieces featured in the suite. Tschaikowsky made a selection of eight of the numbers from the ballet before the ballet's December 1892 première, forming 'The Nutcracker Suite', Op. 71a, intended for concert performance.
The 'Overture' is as well the beginning of the suite as of the entire ballet. It's sometimes called 'Miniature Overture' in English or 'Ouverture Miniature' in French and announces musically the beginning of an exciting fairy-tale: 'One upon a time...'