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
After military service during World War II, Henry Helson (1927-2010) returned to his studies at Harvard. Although his father's recent ancestors had left Eastern Europe to escape pogroms, Henry Helson was determined to cross the Atlantic and do what he could to help with Europe's reconstruction. This article describes his trip, what he learned and observed of the postwar society, and the mathematical life he encountered in Poland.