An endangered species is on view at the National Gallery East Building -- a private collection of old masters. These 57 masterpieces are the sort that seemingly are only within the budgets of museums and foundations to have and to hold these days. But the owner, Baron Thyssen-Bornemisza, is a one-man multi-national conglomerate of old money (German steel) and continuing wise investment, and the paintings are obviously part of the investment.

There is no building theme to the collection other than the quality and vintage (14th through 18th centuries); many nations and many schools are represented. The Baron houses the collection in Switzerland, centers most of his enterprises in Monaco, lives in England partly for tax reasons.

With the outlays that the collection represents, the Baron might have cornered the market on one of the artists, but he apparently judged anything that came on the market by his own sound, wide-reaching and eminent taste. Impulse-shopping on the grandest scale.

There's a Rubens and a Rembrandt, Goyas and Fragonards, a van Leyden and a Carpeccio, Canaletto and a Memling . . . portraits and landscapes, madonnas and still lifes, pastorals and urban plazas. It's grandeur from days long gone and one man's tastes indulged in a way that will never happen again.

At the East Building through February 17.