In this book we highlight and detail the many cases where simulation supports EMC design. In the chapters we also describe the limits, beyond which simulation cannot yet contribute. In this final chapter, we give a list of open problems of EMC simulation. Some of them may be straightforward to solve; others are challenging and may require years of research. In particular for the latter we pose research questions, which shall give an orientation on how to solve these problems. The present list is based on experience and personal favors. It is by no means complete, but it can serve, e.g., PhD students, as a guideline to identify interesting research topics.