This article analyzes the contribution made by Dave Ulrich to debates about the structure of HR departments. It reviews the main developments in his thinking, both before and after the original specification of the key components needed within an HR structure. It discusses associated concepts such as HR architecture and HR delivery models. It outlines some of the proposed mechanisms, and those components of the model that have been most strongly picked up by practice. Finally, it lays out the different ways in which the success of the model might be evaluated.