The master thesis on From skin to leather, from leather to saddle includes theoretical and practical part. Leather as a material for writing, printing and illuminating, its intended purpose, properties and characteristics are explained in theoretical part. Furthermore, the history of the use and the production of leather, including a historical overview of the use of leather and the occurrence of leather as a craftsmanship; the processes, materials and tools used in leather manufacturing are described and the basic differences between parchment and leather from different aspects are shown, such as manufacturing processes and physical, mechanical, chemical or structural characteristics of the listed materials. The third part relates to the basic differences between use and illuminated leather from different points of view, including base/material preparation and the conservation and restoration of both types of works of art itself, accompanied by examples of the use of leather in history, but also conservation and restoration work on these types of artefacts. Then, the fourth part includes the most common damages on leather artefacts, including the most common causes of skin degradation and mechanisms and types of damages, focusing on the highest stage of leather degradation-denaturation of collagen. The last part of the theoretical section is the identification of the most commonly used leather types in history, but also in the conservation and restoration of the same. The practical part relates to conservation and restoration methods on a badly damagedleather bycicle seat, owned by Dubrovnik Museums. This part of thesis describes the condition of the artefact, its origin and artistic and historical context of the artwork. In addition, practical part includes the list of possible treatments, treatment proposal and conservation and restoration practice. Since the prevention is of great importance in further protection of the artefact, some pieces of advice on preservation, storage and display of artwork in line with conservation principles have been given.