Robert M. Grant is a professor and US economic strategy academic who challenged Michael Porter

Michael Porter

Michael Eugene Porter is the Bishop William Lawrence University Professor at Harvard Business School. He is a leading authority on company strategy and the competitiveness of nations and regions. Michael Porter’s work is recognized in many governments, corporations and academic circles globally...

's views on the basis for competitive advantage. He suggested that competitive advantage was more frequently to be discovered in access to distinctive or unique internal resources, rather than a choice between the different forms of generic strategies externally.

Grant is best known for his suggestion that insights into competitive positioning were more likely to come from understanding a company's resource base rather than from its generic strategies. He particularly focused on the extent to which organizations had non-imitable resources.
Grant's work has close links to Gary Hamel

Gary Hamel

Dr. Gary P. Hamel is an American management expert. He is a founder of Strategos, an international management consulting firm based in Chicago.-Early life:...

 and Coimbatore Krishnarao Prahalad – in the form of 'core competencies'

Core competency

A core competency is a concept in management theory originally advocated by CK Prahalad, and Gary Hamel, two business book writers. In their view a core competency is a specific factor that a business sees as being central to the way it, or its employees, works...

. In many ways Grant's 'resources' and Hamel and Prahalad's 'core competencies' overlap to a considerable extent. His concepts have also been taken further by Bowman.