Portfolio management involves centralized management of one or more portfolios, including selecting, prioritizing, and managing work. It helps organizations gain clarity on how to best allocate scarce resources to the most valuable work. The document outlines steps for effective portfolio management implementation, including making a senior executive commitment, determining project scoping and throughput capacity, installing a project scoring model, establishing balance, allowing projects to support strategy, scoring projects based on resources, and following these steps for successful implementation. Effective portfolio management can significantly improve a company's performance.