PMBOK Guide, sixth edition — PMI
A process-oriented reference; detailed rather than a quick implementation manual.
Recommended reading
Project management
Select the amount of process and governance that the work requires.
PRINCE2
A structured governance approach with defined responsibilities; application should be proportionate.
Agile Practice Guide — PMI & Agile Alliance
Supports adaptive and hybrid delivery alongside broader project-management frameworks.
PMBOK Guide, seventh edition — PMI
A principles-led contrast to the sixth edition; less prescriptive about detailed process.
How to use this reading
These are the editions discussed in the original reading collection, not a claim that they are the latest. Compare process, governance and adaptability before selecting an approach.