Master index v5 of the F=∇(1/N) Unified Physics Series by Yoshimitsu Katayama. 13 papers across four series. New in v5: Paper 13 — The Critical N-Gradient: compassion (慈悲) as physical ∇_max management, the middle path (中道) as optimal gradient for maximum sustained value flow, economic collapse as interface failure when ∇(1/N) exceeds ∇_max. One equation F=∇(1/N) unifies physics, materials, biology, economics, and moral law.