Multi-agent systems are nowadays at the core of the emerging Agentic AI field, providing the conceptual and computational foundations for building intelligent systems composed of interacting autonomous entities. These systems consist of multiple agents that engage with one another and with their environment to achieve individual and collective goals. The contributions in this volume place multiagent abstractions at the heart of intelligent systems research, raising deep and novel research questions. Collectively, they offer the reader a conceptual path tracing the evolution of the domain over recent decades, while outlining future perspectives. Specific approaches discussed include trust, self-organization, multiagent-based simulation, formal models for multiagent systems, MAS protocols, and applications in software engineering and distributed systems. Inspired in part by the success of the workshop From Objects to Agents (WOA), the contributions in this open access volume will be valuable for researchers in agent systems, AI, software engineering, and networking.