Since the start of the Historical Microscopy Foundation in 1987, Jan Deiman (MSc, PhD) is involved as advisor. Jan studied electrical engineering at Delft University of Technology (TU Delft). In his spare time he worked as conservator at the division Electrical Engineering. He graduated on the history of the compensator. After finishing his study in 1984, Jan became responsible for the collection of scientific physical instruments at the Utrecht University Museum with a specialisation on the 300 historical microscopes. He started working as the assistant of J. van Zuylen, former head of the Physical Laboratory of the Bleeker (Nedoptifa) company in Zeist. In 1988, G. L’Estrange Turner asked Jan to start a PhD study in England at the het Imperial College of Science, Technology and Medicine in London. Between 1989 and 1921 Jan did research on hundreds of microscopes of the collections of the Science Museum in London and the Royal Microscopical Society in Oxford. The result was the dissertation Microscope Optics and J.J. Lister’s Influence on the Development of the Achromatic Objective 1750-1850. His knowledge of microscopes is valuable for the foundation. Jan gives advice on new acquisitions and makes the descriptions of the microscopes and scientific instruments. At this moment he lives in Ubud, Bali.