"Other, far fewer, directors are more like the composer - conceptualizing the piece, scoring it, distributing its musical lines among a range of registers, chords, and instruments"

This quote by Thomas Harrison is referring to the function of a director in the imaginative process. He is suggesting that some directors are more like authors because they have the ability to conceive the piece, score it, and disperse its musical lines amongst a variety of registers, chords, and instruments. This indicates that these directors have a strong understanding of music theory and structure, and have the ability to develop a piece of music from scratch. This type of director is far less typical than those who just analyze a piece of music that has actually currently been composed. This quote is highlighting the significance of having a director who has the ability to develop a piece of music from the ground up, as this type of director has the ability to bring a special and innovative point of view to the project.