This pocket guide explains the content and the practical use of ISO 21500 - Guidance on project management, the latest international standard for project management, and the first of a family of ISO standards for project, portfolio and program management. ISO 21500 is meant for senior managers and project sponsors to better understand project management and to properly support projects, for project managers and their team members to have a reference for comparing their projects to others and it can be used as a basis for the development of national standards. This pocket guide provides a quick introduction as well as a structured overview of this guidance and deals with the key issues within project management: • Roles and responsibilities • Balancing the project constraints • Competencies of project personnel All ISO 21500 subject groups (themes) are explained: Integration, Stakeholder, Scope, Resource, Time, Cost, Risk, Quality, Procurement and Communication. A separate chapter explains the comparison between, ISO 21500 and PMBOK® Guide PRINCE2, Agile, Lean, Six Sigma and other methods, practices and models. Finally, it provides a high level description of how ISO 21500 can be applied in practice using a generic project life cycle. Proper application of this new globally accepted project management guideline will support organizations and individuals in growing their project management maturity consistently to a professional level.