Master index v4 of the F=∇(1/N) Unified Physics Series by Yoshimitsu Katayama. Now covers 12 papers across four series: Series I (Core Forces), Series II (Structural Applications), Series III (Materials and Life Science), Series IV (Economics and Value Theory). New in v4: Paper 10 (3D Corrosion), Paper 11 (5D Corrosion in x,y,z,t,λ — color as N-field readout), Paper 12 (Gold Coin in the Wallet — economic emanation from N-gradient). One equation F=∇(1/N) unifies physics, materials science, biology, and economics.