A magnificent obsession. (art collectors Dorothy and Herbert Vogel)

The Vogels are not typical art collectors. They are not rich, yet they managed to collect more than 2,000 works of art by living frugally. The National Gallery will exhibit 89 pieces from their collection in the genres of conceptualism, minimalism and post-minimalism.

THE National Gallery of Art in Washington, DC, was founded by one plutocrat, Andrew Mellon, and has been generously endowed by many others, including his son, Paul. As with most American museums, its collection reflects the enthusiasms of rich men for blue-chip old and modern masters.

In such company, Dorothy and Herbert ...