PRINCE2 (Projects In Controlled Environments), is a process-based method for effective project management. It was published in 1996 and is used extensively by the UK government.

The PRINCE2 method offers non-proprietorial
best practice guidance on project management:

Focus on business justification
Defined organization structure for the project management team
Emphasis on dividing the project into manageable and controllable stages
Flexibility that can be applied at a level appropriate to the project
Product-based planning approach
Other Methodologies
PMBOK GuideAgile