The term LIBRETTO is a combination of the words 'BOOK', 'TEXT' and 'LYRIC'. It is used to refer to a small BOOK or pamphlet containing the words of an opera, operetta, or musical play. The libretto is usually written by a poet or librettist and contains the story line, character descriptions, and stage directions. It is often accompanied by music composed by a composer. Librettos are typically printed in a small format and are often used as souvenirs or keepsakes for those who attend the performance.