Under music director Leon Botstein, the ASO has pioneered the concept of presenting concerts curated around various themes drawn from the visual arts, literature, politics, and history, and unearthing rarely performed masterworks for well-deserved revival. These concerts are performed in the Vanguard Series at Carnegie Hall. The ASO seeks to preserve the rare works it performs from disappearing from the repertoire. While some rare works are available with complete parts and a score in usable condition, others require extensive restoration and even creation to render them performable. ASO’s efforts to create these parts mean that these works are now available for performance by other orchestras.