In 2007, IBM Research took on the grand challenge of building a computer system that could compete with champions at the game of Jeopardy!™. In 2011, the open-domain question-answering (QA) system, dubbed Watson, beat the two highest ranked players in a nationally televised two-game Jeopardy! match. This paper provides a brief history of the events and ideas that positioned our team to take on the Jeopardy! challenge, build Watson, IBM Watson™, and ultimately triumph. It describes both the nature of the QA challenge represented by Jeopardy! and our overarching technical approach. The main body of this paper provides a narrative of the DeepQA processing pipeline to introduce the articles in this special issue and put them in context of the overall system. Finally, this paper summarizes our main results, describing how the system, as a holistic combination of many diverse algorithmic techniques, performed at champion levels, and it briefly discusses the team's future research plans. © 1957-2012 IBM.