This report brings together over fifty essays by policymakers, researchers and practitioners to propose Global Public Investment (GPI) as a new approach to financing global challenges beyond traditional aid. The collection sets out the rationale for GPI, its core principles of all contribute, all decide and all benefit, and explores how a more inclusive, predictable and collectively governed system of public finance could support shared global goals such as climate action, health, social protection and crisis response. Through thematic and regional contributions, the report examines how GPI could reshape international financial cooperation and complement existing development and humanitarian financing mechanisms.