Over the past few years of slumping art sales, one overarching theme has been the enduring strength of the market for design objects. Lately, though, it has become clear that the two diverging paths in the market were not an anomaly but the beginnings of a new phase of collecting—one that incorporates design as a grounding principle. This season, Sotheby’s is making that connection explicit with the installation of two collections that forgo the emphasis on individual objects, or even the unifying theme of the collectors behind them. Instead, they emphasize the integration of art and design into a gesamtkunstwerk that is greater than the sum of its individual parts.