Gerard Albert Cornelius de Graaf, born on February 4, 1928, in Amsterdam and passed away on April 12, 2013, was a distinguished master organ builder. In 1958, he founded his own workshop in Amsterdam before relocating it to El Carpio de Tajo, Spain, after several years. His move marked a significant transition in his career, bringing his craftsmanship to a new cultural and geographical context. Additionally, de Graaf was a co-founder of the International Society of Organ Builders (ISO) in 1957, highlighting his influence and active participation in the global organ building community. Throughout his life, de Graaf contributed significantly to the field of organ building, blending his Dutch heritage with his experiences in Spain. His legacy includes not only the organs he built and restored but also his role in fostering international collaboration and standards in organ construction through the ISO. His death marked the end of a prolific career that had a lasting impact on the craft of organ building. Source: Pipe Organ Map website, referencing Gesellschaft der Orgelfreunde e.V.