The Circle of Fifths is a visual representation of the relationships between the 12 tones of the chromatic scale. It arranges these tones in a circular format, where each note is a perfect fifth apart from its neighbors. This tool helps musicians understand key signatures, chord progressions, and the structure of music. In the Circle of Fifths, moving clockwise from any note adds sharps to the key signature, while moving counterclockwise adds flats. This makes it easier to identify related keys and transitions in music composition, enhancing both songwriting and improvisation skills.