Scrum is not a method . It promises only that the team is always working on the most important thing.
Scrum is only a framework. In most cases it doesn’t tell you what to do , nor how to do things. Its a project management framework that you fill in , within which you inspect and adapt to optimize ROI.
Scrum principles apply to companies ranging from automobile manufacturing to churches.
This is how things came together within Easel . They used some Smalltalk ® engineering tools. This came together in 1993. The first scrum took place at the Easel Corporation in 1993, some four years before XP would appear. The foundations of Scrum include the paper by Hirotaka Takeuchi and Ikujiro Nonaka in Harvard Business Review that talked about issues related to knowledge management . Lean principles are also a major foundation, as are Iterative and Incremental development and time boxing.
Easel used a Smalltalk tool set . All of this, combined with the concept of morning Scrums that came from the Borland Quattro Pro for Windows Project, cooked together into scrum.