Many new products, or services offered as a product, are expected to solve customer problems in new ways or exploit available technology in new or better ways. To innovate, a company needs to have a reliable understanding of the state-of-the-art. That need concerns both, an understanding of the problems that may be addressed and the solutions that have been explored and tried so far. This paper proposes systematic mappings as a method for reviewing the state-of-the-art in a technological or application domain. The method complements bespoke and experience-based approaches by guiding the identification of repositories with information about innovation projects and the analysis and interpretation of the data provided by these repositories. The paper describes the method, demonstrates its application with an example initiated by real-world innovation need, and discusses the potential benefits and limitations of the method.