As the field of international business (IB) has continued to evolve, a proliferation of new theories, frameworks, and concepts have been developed and applied to explain IB phenomena. While new insights and research streams are essential to the vitality of any field, in the case of international business, it can, at times, appear as if the core theories are being forgotten or overlooked at best, and misunderstood at worst. To advance our thinking about IB theory, Professor Mark Casson, one of the originators of the theory of the MNE, was commissioned to invite and referee a set of state-of-the-art papers on this topic.

In this special issue on the theory of IB, we are pleased to help refocus the field of international business on core theories by publishing five papers which revisit, consider, and explain the multinational enterprise and the importance of internalization theory to its analysis.