Stuart Russell is a leading AI researcher who literally wrote (well, co-authored) the top textbook on the topic. He has also, for the last several years, been warning that his field has the potential to go catastrophically wrong. In a new book, Human Compatible, he explains how. AI systems, he notes, are evaluated by how good they are at achieving their objective: winning video games, writing humanlike text, solving puzzles. If they hit on a strategy that fits that objective, they will run with it, without explicit human instruction to do so.

Google's DeepMind artificial intelligence team is making history. Its AlphaGo program is up 2-0 on Lee Sedol, one of the top Go players alive. This is the first time a computer has beat a human champion without a handicap. While there will be three more games between Sedol and AlphaGo, the victory suggests that Go is the latest game that computers are outwitting people in. Checkers fell in 1994, Chess in 1997, and Jeopardy in 2011. "It there's a social component with players playing together, it's not clear," Littman says.