INTRODUCTION (Lat. introductio. a lead ing in, from introducere, to lead in. from intro, within + duccre, to lead). In instrumental music, a shorter movement preceding the com position proper. According to the character and length of the composition the introduction may be shorter or longer. In a polonaise, waltz, etc.. the introduction generally consists of only a few bars. In works written in sonata form the in troduction can assume great dimensions. as in Beethoven's Second and Serenth Symphonies. The thematic material upon which the introduc tion is built. may be entirely original and inde pendent of any themes in the following principal movement, as in the case of the two Beethoven symphonies. Then again the introduction may be constructed upon themes of the movement proper, as in the ease of Schumann's First Sym phony. As the introduction is invariably in a slow tempo, the themes of the allegro appear almost invariably in augmentation when used in the introduction. But it is by no means obliga tory to begin every longer composition with an introduction. Of Beethoven's symphonies the
third. fifth, sixth, eighth, and ninth begin with out any introduction.
In dramatic music the term introduction has several meanings. In the older operas. which were divided into numbers, the introduction was the second number. It followed the overture, and generally was a short instrumental passage leading into the opening chorus. But even Gluck sometime% united the overture with the intro duction. Some operas have no overture, but only an introduction of greater or less extent. Such works as Verdi's Otello or Falstaff have, properly speaking. not even an introduction. Beginning with Lohenprin, Wagner abandoned the form of the overture and substituted an in troduction which he calls Vorspiel (q.v.). Be sides the principal introduction at the beginning of his dramatic works. \\ agner generally opens eu cry act with an introduction of some length,