A Guide to the Project Management Body of Knowledge (PMBOK® Guide) is a guide providing a comprehensive set of knowledge, concepts, techniques and skills for the project management profession.

The PMBOK® Guide is a publication of the Project Management Institute, an entity that is recognized as governing the discipline. PMI was founded in 1969 in the US and has become one of the principal professional non-profit organizations in the specialism. The first edition was published in 1996; the latest English-language PMBOK® Guide - Fourth Edition, was released in December 2008.

The PMBOK® Guide is process-based: it describes work as being accomplished by processes. This approach is consistent with other management standards such as ISO/IEC 9001:2008 and the Software Engineering Institute’s CMMI. Processes overlap and interact throughout a project or its various phases. Processes are described in terms of inputs (documents, plans, designs, etc.), tools and techniques (mechanisms applied to inputs) and outputs (documents, products, etc.) The guide identifies 42 processes that fall into five basic process groups and nine knowledge areas that are typical for almost every project.

The five process groups are Initiating; Planning; Executing; Monitoring and Controlling; and Closing.

The nine knowledge areas are Project Integration Management, Project Scope Management, Project Time Management, Project Cost Management, Project Quality Management, Project Human Resource Management, Project Communications Management, Project Risk Management and Project Procurement Management. Each of the nine knowledge areas contains the processes that need to be accomplished within its discipline in order to achieve effective management of a project. Each of these processes also falls into one of the five basic process groups, creating a matrix structure such that every process can be related to one knowledge area and one process group.