For 7 years, IBM researchers toiled to build a machine that could understand and answer spoken questions. In 2007, the company invited computer scientists from Carnegie Mellon University (CMU) to two workshops at its research center in Yorktown Heights, New York. For CMU graduate student Nico Schlaefer, the workshops were a turning point. As an undergraduate at the University of Karlsruhe, Germany, and a visiting scholar at CMU in 2005, Schlaefer had built a question-answer system called Ephyra. Impressed, IBM offered Schlaefer a summer internship with the project—the first of three he spent working on Watson. Last week, Schlaefer, now a Ph.D. candidate in computer science at CMU and an IBM Ph.D. Fellow, told Science about the algorithm he contributed to the now-world-famous computer.