
As the most important and influential physicist of the twentieth century Albert Einstein is a favorite subject for historians of physics. I am no exception in that respect. But although I have published some papers on aspects of Einstein’s work, and on his relationship with the Dutch physics community—he was permanent guest professor in Leiden from 1921 on—I made my main contributions to Einstein scholarship as an editor of the Collected Papers of Albert Einstein. From 1985 on I have been connected with the Einstein Project, in various capacities—but always part-time, next to my work in Amsterdam. Until 2025 I was a Senior Editor at the Project as well as a Visiting Associate in History at the California Institute of Technology, spending between two and four months each year in sunny California. Nowadays I am a regular contributor. The first Einstein volume appeared in 1987, the most recent one, Volume 17, was published in 2024. There are at least thirteen more volumes to come, which will take more than thirty years to complete. A rather daunting prospect.