This book constitutes the refereed proceedings of the 13th International Symposium on Frontiers of Combining Systems, FroCoS 2021, held in Birmingham, UK, in September 2021.

This book constitutes the refereed proceedings of the 17th International Conference on Runtime Verification, RV 2017, held in Seattle, WA, USA, in September 2017. The 18 revised full papers presented together with 3 invited presentations, 4 short papers, 5 tool papers, and 3 tutorials, were carefully reviewed and selected from 58 submissions. The RV conference is concerned with all aspects of monitoring and analysis of hardware, software and more general system executions. Runtime verification techniques are lightweight techniques to assess correctness, reliability, and robustness; these techniques are significantly more powerful and versatile than conventional testing, and more practical than exhaustive formal verification.