In 1968 Palle Nielsen approached the Moderna Museet in Stockholm with a proposal for turning the museum into an adventure playground. From 30 September to 20 October 1968 Modellen. En modell for ett kvalitativt samhalle (The Model - A Model for a Qualitative Society) was installed and children under eighteen were offered free access. The event attracted more than 35,000 visitors. Nielsen's insistence on using institutional space for advancing artistic critique was precocious, prefiguring activist uses of the white cube. This book presents a selection of the material donated to the Museu d'Art Contemporani de Barcelona (MACBA) by Palle Nielsen in 2009, and shown the same year as part of the exhibition Time as Matter. MACBA Collection. New Acquisitions. It includes an essay by Lars Bang Larsen, various texts by Palle Nielsen as well as the artist's documentary photos from The Model."