Today, composers and musicians make use of major and minor key signatures. If they did not, too many flats and sharps would have to be used in some cases -- and the key signature at the beginning of a composition applies to the entire song, unless it is replaced by another key signature or canceled by the same number of naturals. As shown below, specific notes are either sharpened or flattened, depending on the signature used (x). If one does not read the key signature, one will not know which notes to sharpen or flatten. Note the use of Fb or E in the last measure, and E# or F. In the last measure, two naturals are also used to cancel the application of a sharp (Key of A) and flat (Key of Eb). No double sharps or flats are present. Accidentals come in four varieties and indicate whether to raise or lower the note they are applied to.

	C#, G#, F#, G#, F#, G#, E#
	Ab, Bb, Eb, Bb, Ab, Fb