Climate change, poverty, and inequality are deeply intertwined, and tackling them together is essential as countries plan, implement, and manage the infrastructure and investments that underpin the world's economies. Trade-offs are inevitable, and policy makers require new information, tools, systems, and capabilities to make informed decisions. This reference guide brings together in one place the resources that have been developed to embed climate change within public investment management (PIM) systems and the policies and processes that inform PIM's design and implementation. Public investment is a central tool for governments to prepare for and address the impacts of climate change. A policy-led, two-pronged approach is required to address Paris Agreement commitments while protecting the public: large-scale decarbonization and adaptation to climate change impacts. "Decarbonization" is the term used in this guide to signal the overall goal of cutting the equivalent emissions of carbon dioxide (CO2) from all Greenhouse Gas(GHGs). This reference guide seeks to help policy makers and actors in the public and private sectors to meaningfully address such challenges. Climate action requires deliberate strategies, backed by actionable plans, followed by rigorous implementation. This reference guide focuses on two key phases of climate-informed investment management: upstream public investment policy (PIP) and downstream implementation of those policies through PIM.