This CIGRE Green Book describes the state-of-the-art of power Systems asset management dealing with all aspects asset management practice. The major focus of the book is on documenting practical methods that bridge the gap between just satisfying an asset management process and achieving real asset management results in the form of smarter investment decisions. The book facilitates collaboration and blending of the engineering and technical aspects of asset management and the financial considerations needed to support asset investment decisions using risk-based business case analysis. Detailed case studies are included to illustrate generic and specific or customized methods and to demonstrate the application of such methods from the technology perspectives of several CIGRE study committees. This practical guide is suitable for working asset managers and decision-makers (both engineering and financial) dealing with all aspects of the practice of asset management.