Musical instruments, as an integral part of cultural and historical heritage, possess not only artistic and aesthetic values but also significant scientific, technical, and musical aspects. Due to the per formative nature of music, musical instruments are susceptible to wear and deterioration, presenting unique challenges for their preservation and restoration. Unlike many historical artifacts that are restored solely to preserve their physical structure and prevent decay, the restoration of musical instruments must consider the aesthetic sonic concepts of the work in addition to preserving its cultural and historical identity. Any intervention in these instruments should be carried out in a way that does not negatively affect their sonic and structural authenticity. In some cases, due to the high sensitivity of historical instruments and the potential for physical damage during studies and investigations, researchers have resorted to reproducing similar examples. This requires precise knowledge of the organ logy of the instruments and their construction techniques in different historical periods. In this research, the historical introduction and classification of instruments are presented first, and then the structural characteristics of each group are examined. Subsequently, study strategies appropriate to the characteristics of each historical group are provided, and the theoretical foundations for the preservation and restoration of musical instruments are developed. The results of this research show that the restoration process of historical instruments, due to their structural and acoustic diversity, requires different approaches and a deep awareness of the physical and sonic characteristics of each instrument. Therefore, restorers must have a comprehensive understanding of the acoustic dimensions and materials of the instruments before any intervention to strike a balance between physical preservation, sonic reproduction, and the preservation of cultural authenticity.
