Given the heavy infusion of music in the text and the central role it plays in the relationship between the two protagonists, structuring the Rose series as a symphony came naturally. Peter's fascination with Mozart would suggest a classical structure with four movements, yet, the books follow the Italian style with only three movements. First, Mozart did compose many symphonies in that style in his earlier years, before he later helped develop the more elaborate classical symphony. Second, a book is no musical piece. While composers of pieces without a libretto are free to string together motives almost at will and revisit and develop them, a book has to move towards a climax in a consistent fashion. Repeating and varying motives, while possible and used throughout the Rose series, are constraint by the overall storyline.

The series follows a three-movement Sonata form with each movement represented by one book. Each book has its own central theme and "tempo," with more fast-paced action in books one and three, and a slower moving book two. Although each Book in the trilogy itself follows Sonata form, the parallels start to break down. The organizing principle of books in chapters does not really match Sonata form. The need to keep the story moving along, while introducing characters and surroundings, also does not lend itself to a strict adherence to the fast-slow-fast structure of the classical Sonata form. "Romy" does have that overall structure, with each "movement" taking up roughly a third of the book.

The series also has three parts of roughly equal length. Adhering to the classical symphony form would have added a shorter third movement in a contrasting style of a Minuet or Scherzo. That would have meant a short separate book that probably could not stand on its own. To maintain the symmetry of the books the Italian form with three equally structured movements was chosen. It is possible that a combined edition of all parts may include a lighthearted Scherzo of less than a hundred pages to complete the classical symphony.