In project management (and any other sort of management really) proper stakeholder management can mean the difference between success or failure. Although process and system changes are often the focus for a project, the people involved was inevitably what really pushed the project across the line or tanked it.
The Prince2 definition of a project is a temporary organization that is created for the purpose of delivering one or more business products according to an agreed business case. PMI defines a project as follows: A project is temporary in that it has a defined beginning and end in time, and therefore defined scope and resources. And a project is unique in that it is not a routine operation, but a specific set of operations designed to accomplish a singular goal.