Madonna's music has been the subject of much analysis and scrutiny. Robert M. Grant, author of Contemporary Strategy Analysis (2005), commented that what has brought Madonna success is "certainly not outstanding natural talent. As a vocalist, musician, dancer, songwriter, or actress, Madonna's talents seem modest." He asserts Madonna's success is in relying on the talents of others, and that her personal relationships have served as cornerstones to the numerous reinventions in the longevity of her career. Madonna's approach was far from the music industry wisdom of "Find a winning formula and stick to it." Her musical career has been a continuous experimentation with new musical ideas and new images and a constant quest for new heights of fame and acclaim. Grant concluded that "having established herself as the queen of popular music, Madonna did not stop there, but continued re-inventing." Musicologist Susan McClary wrote that "Madonna's art itself repeatedly deconstructs the traditional notion of the unified subject with finite ego boundaries. Her pieces explore various ways of constituting identities that refuse stability, that remain fluid, that resist definition."