Beyond the reverse product cycle: An exploration of the digital, social and spatial transformation of libraries11We sincerely thank the anonymous reviewers for their insightful comments and suggestions, which significantly helped enhance our article

Focusing on innovation dynamics in public libraries, this article begins by revisiting one of the very first attempts to construct a theory of innovation in services: the reverse product cycle (RPC), published in Research Policy (Barras, 1986, 1990). With reference to ICT-based innovation trajectories in libraries, the article validates the RPC by identifying a cycle that begins with a stage dominated by process innovations, followed by one dominated by product innovations. It goes further by extending – and in some respects updating – the model, taking into account forgotten technologies and introducing new waves of enabling technologies associated with Industry 4.0 and 5.0. The rise of the internet and digitization posed an existential threat to libraries. Their survival, however, is due to their ability to reinvent themselves – transforming this threat into an opportunity, and embracing innovative trajectories that aren't solely ICT-based. These include book-, object-, individual-, and space-based trajectories.