In his essay on the authorial performance tradition, Hermann Danuser distinguishes four means through which composers can transmit their ideas of the interpretation of their works: ‘first by performance instructions given in the text of the work, second, by their conception of performance communicated orally or in writing, third, by the realization of “exemplary” performances, and fourth, by fixing the authorial performance on a recording medium in the twentieth century’.
Bartók utilized all these opportunities to convey his ideas of the performance of his music throughout his career. He edited his compositions carefully with an abundance of descriptive expressions and signs, indicating tempo and character, phrasing, dynamic shading, articulation and accents, their combinations, sometimes introducing novel signs for special effects. To further define the character of the composition, he indicated the tempo and tempo changes with metronome markings, and from the 1930s, he also started to provide the expected time to perform the work in the score at the end of each composition or individual movement.
Most of the elements of Western musical notation, however, are only approximations and need interpretation. There are conventions that the composer may take for granted but these might become forgotten in time. For this reason, any clarification about musical notations by a composer represents inestimable value. However, even armed with the systematic explanations of the performing signs Bartók employed in his instructional editions of classical music, there remain uncertainties in the interpretation of the score since certain nuances cannot be noted in a practical way without becoming too complicated and obscuring basic elements of the composition.