In the summer of 1937, Walter Gropius, founder of the Bauhaus and a professor at Harvard's new Graduate School of Design, rented a house on Planting Island, near the base of Cape Cod. There, he and his wife, Ise, hosted a festive reunion of Bauhaus masters and students who had recently emigrated from Europe: Marcel Breuer, Herbert Bayer, Laszlo Moholy-Nagy, Xanti Schawinsky and others. Together they feasted, swam and planned their futures on a new continent, all sensing they were on the cusp of a momentous new phase in their lives. Yet even as they moved on, the group never lost its...