In 1611 Johannes Kepler published a conjecture on the tightest way to pack unit spheres in 3-D. In April 2000, Thomas Hales described his proof here in the Notices. Our cover story reports that last year Maryna Viazovska proved the 8-D case, promptly followed by a collaborative proof in 24-D. Meanwhile, as described in our second feature article, Stanley's Partitionability Conjecture has been disproved by a counterexample. The Graduate Student Section features an interview with Tom Grandine, senior technical fellow at Boeing Company, and "WHAT IS...Benford's Law?" A new Mathematical Moment on "Maintaining a Balance" vs. global environmental catastrophe has an accompanying deeper explanation by MIT climate scientist Daniel Rothman. This issue also includes an article on active learning, a report on The Bridges Conference—the world's largest interdisciplinary conference on mathematics and art, a new BookShelf, a book review examining recreational math, and a firsthand account of a Fulbright Specialist's time in Qatar. The BackPage has a special comic on refereeing and the Super Bowl. —Frank Morgan, Editor-in-Chief