Annabelle Selldorf’s discreet plan to renovate the 1914 mansion on the Upper East Side of Manhattan frames views to the museum’s Russell Page–designed garden.

For more than a year, New Yorkers have waited to learn the outcome of a forthcoming expansion of the Frick Collection, the beloved Manhattan institution known for its intimate scale as much as for its collection of works by Vermeer, Rembrandt, Turner, and other masters.