Enlightening ET Article About Incompetency Assessment - The Peter Principle

Hello HR Skippers,
Please find attached a very Enlightening ET article about Incompetency Assessment i.e. The Peter Principle.

really good idea. I feel organisations have more focus on the competencies. while promoting or not promoting, this mis focus bears more weight and hence, incompetencies will not be addressed. I do not know the theory, but certanly feel that even not promoting also will develop some incompetencies. Please provide the link/copy of the book mentioned if it is available.
Regards
Phani Kumar P