Libraries in the sky: large-scale collaboration strategies and infrastructures to enhance the use of digital heritage collections. The IFLA Rare Books and Special Collections is inviting speakers from all over the world to Oslo on April 12th, 2018, to present their experiences and projects regarding the building of large-scale collaborative tools and infrastructures to enhance the access to and the reuse of digital heritage collections, born-digital or digitized items. An interactive training session on IIIF will also be provided by the National Library of Norway.