Clutching a cup of morning coffee, writer and art world raconteur John Richardson is padding around his 5,000-square-foot loft on lower Fifth Avenue in Manhattan, an enfilade of high-ceilinged, classically proportioned rooms redolent of haute bohemia. It’s the day after the launch party for A Life of Picasso: The Triumphant Years, 1917–1932, the third volume…

The treasure-filled Malplaquet House, the formerly dilapidated mansion in London’s East End, is home to Tim Knox, director of the venerable Sir John Soane’s Museum in Lincoln’s Inn Fields, and his partner, renowned landscape architect Todd Longstaffe-Gowan.