Revision with unchanged content. Almost half a century of diversification research supports the suggestion that related resources lead to a superior performance of multibusiness firms. Nonetheless no direct measurement concept on a complete resource base of a single business function exists up to now. This book is focusing on this gap and the understanding of R&D. Besides the core question of relatedness there are two main hypotheses developed: Is relatedness similar to the potential synergies of a resource which is tested to be significantly true while knowledge based resources are tested not to be more important for the success of R&D than others. The results suggest that three resources are most important in terms of relatedness. These are analysed and categorised on a more detailed sub-level to identify the related resources of R&D units but also to highlight the degree of relatedness within these resources. The measure is able to offer one overall relatedness value that shows to what degree R&D departments within a multibusiness firm are related. Hence this book offers interesting implications for oncoming studies on measuring relatedness, as it does for practitioners who want to measure the relatedness of R&D.