In this post, we are providing a historical perspective on the PMBOK Guide, especially with the sixth edition coming out soon.
The first official consolidated copy of the PMBOK® Guide was published in 1996. It was about 180 pages; it had 37 processes, nine knowledge areas, and five process groups. This first edition did not have an ANSI standard.
PMI came out with the second release, under the label ‘the 2000 Edition.’ With this version, the number of processes increased to 39, the number of pages increased to about 210; the two additional processes were in the risk knowledge area, and with this edition, there were some changes to the names of the processes. This second edition was still not labeled as an ANSI standard.
With the 2004 edition, PMI started to number the versions and calling this version the Third Edition instead of the 2004 edition.
Chapter 3 was split from the first part of the book and listed on its own under the title ‘The Standard for Project Management of a Project.’ This change was likely due to ANSI approval.
Other modifications in this edition were the increase in the number of processes from 39 to 44. Most of the changes were in the integration chapter with the addition of four processes. Further, some processes moved from one knowledge area to another. The number of pages reached about 400 pages.
With this edition, there were no changes to the sections or knowledge areas. The number of processes dropped to 42 by consolidating six procurement processes into four. Other changes were affecting the names of processes, moving some of them from one knowledge area or process group to another. Further, there was the usual additions or deletion of certain processes.
With this edition, the number of pages jumped to more than 600, which included a new knowledge area and the number of processes increased from 42 to 47.
Most of the content of the additional processes were there before, incorporated into other processes. For example, three of the five other processes are the management planning processes (for scope, time and cost) and they were part of the Develop Project Management Plan process in the integration chapter of the fourth edition. However, with the fifth edition, these sub-processes became independent processes, each in its respective knowledge area. Although this change resulted in three of the five additional processes, it was mostly relocating the action from one place to another. It was also overdue for consistency since, before this change, all of the other knowledge areas had a management plan process.
The picture below shows the change in the relative size of the book. The official 2000 edition is not here but a translated copy of it is here. The second book from the bottom is the 2000 edition but in English and Arabic — so it is double the size of the English version.
Next, the table summarizes the general changes from the first to the fifth edition of the PMBOK® Guide.
At the time of finalizing this book, PMI has not published the sixth edition yet, but there was a release of the exposure drafts of the standard section (the ANSI approved one) and the Guide. Some of the changes were the shift of the name of the Project Time Management knowledge area to Project Schedule Management and the replacement of Project Human Resource Management with Project Resource Management encompassing all resources not only people; this is a more substantial change. There are also the common changes, adding a process here, deleting one there, and moving a process from one section to another. One substantial change seems to be replacing Chapter 3 with a chapter on the project manager role.
Since not all of the changes are known yet, it is not possible to address them here. However, reviewing the exposure draft, it would be logical to say that most of the changes do not have an impact on this book. There might be minor adjustments, but the core concepts are unchanged, which means the core message of this book would still be applicable and not affected.
 In the 1996 and 2000 editions, Part 1 consisted of the first three chapters.
 Three added processes: Plan Scope Management, Plan Time Management, and Plan Cost Management (PMI, 2013)
 Process Groups
 Knowledge Areas
 This article is extracted from a book that we are publishing and will be released this summer. However, this chapter was deleted from the book.