Flipping back through old photos of Marjorie Merriweather Post, author Allison Pataki admits she gets a little emotional when she catches the eye of the late socialite staring back into the camera.

Hillwood Estate was the home of breakfast-cereal heiress Marjorie Merriweather Post. She collected art from 18th-century France and imperial Russia for display in her 36-room mansion. Hillwood was her ...