Disaster risk reduction mainstreaming involves integrating disaster risk reduction considerations into development planning, policy$-$making, and investment decisions across sectors and levels of government. Explore the theoretical foundations of disaster risk reduction mainstreaming, including concepts such as risk$-$sensitive development, multi$-$sectoral collaboration, and policy coherence. How do policymakers and practitioners apply theoretical models of disaster risk reduction mainstreaming to embed risk reduction principles into development processes, improve resilience$-$building efforts, and reduce vulnerability to disasters in at$-$risk communities?