The present first part of the RKD Study Frans Hals and his workshop comprises three monographic chapters on the life, work and reception of Frans Hals. The author devotes particular attention to his theory on Hals’s workshop practice and the collaboration with other artists. Thanks to new insights gained by technical research, as well as new possibilities for comparing and analyzing works of art in minute detail – using high-resolution digital photographs – Claus Grimm now distinguishes which paintings, or which parts of them, were executed by Hals himself and which were done by studio assistants. A large number of details is reproduced in the publication, providing insight into the arguments for accepting or rejecting specific attributions.