Cross-industry innovation introduces a dilemma for the innovation process. On one hand, there is a broad consensus in research that diversity in knowledge leads to increased levels of novelty in innovation. On the other hand, the crossing of industries boundaries is known to cause knowledge boundaries between actors. This book contributes to this end, by the development of new understanding of important aspects in cross-industry innovation. The empirical bases for this research are case data from the Pumps & Pipes association in US and Norway (conferences and 7 Norwegian cross-industry collaborations), and cross-industry cases from the Norway Health Tech cluster.