The set of papers collected in this issue originated from the AGERE! Workshop series - the last edition was held in 2017 - and concern the application of actor-based approaches to mainstream application domains and the discussion of related issues. The issue is divided into two parts. The first part concerns Web Programming; Data-Intensive Parallel Programming; Mobile Computing; Self-Organizing Systems and the second part concerns Scheduling; Debugging; Communication and Coordination; Monitoring. 86 Illustrations, black and white; IX, 245 p. 86 illus.