The objective of this qualitative study is to examine the use of talking books in school libraries in Sweden, and to identify the key factors for using the Legimus app successfully. There are several laws, regulations and policy documents concerning the educational function of school libraries which specifically mention pupils’ right to learn taking into account their own specific circumstances. The situation, however, varies greatly around the country. The way in which school librarians work with Legimus is crucial for students with reading difficulties, and for their development and reading ability. Three points will be addressed: How do school librarians work with Legimus? Which factors of success can be found? What challenges do the school librarians encounter when working with Legimus? To investigate these issues, seven semi-structured interviews were conducted with school librarians in three different regions of Sweden during the fall of 2019. The material has been analysed from a sociocultural perspective, through the application of the concepts social practice, mediating tools and appropriation of cultural tools. The study shows that the work of the school librarians takes place inside, and is formed by, a social practice where action patterns, routines and work processes are shaped in relation to the specific context. The study further shows that teamwork plays a key part in working with Legimus, and that the school librarian cooperates with other professions, such as educational specialists, teachers, school computer technicians, head masters, and also with guardians. Well-developed joint effort, resources such as school librarians and other school staff, availability of technical equipment and the normalisation of listening as a method of reading, can all be identified as factors of success. The challenges identified were lack of continuity, insufficient competence of the school librarian and problems with the technical equipment.