Cool Stars in the Hertzsprung-Russell Diagram

Jacco Th. van Loon

Published 2015-11-20Version 1

As the opening review to the focus meeting ``Stellar Behemoths: Red Supergiants across the Local Universe'', I here provide a brief introduction to red supergiants, setting the stage for subsequent contributions. I highlight some recent activity in the field, and identify areas of progress, areas where progress is needed, and how such progress might be achieved.