Hitler hated -- and nearly destroyed -- much of the finest German art of his time. But many works escaped, and some of the great survivors have just gone on view at the National Gallery of Art, East Wing.

The show of 76 powerful works by the best 20th-century German Expressionists, Constructivists and Bauhaus artists -- Barlach, Kirchner, Feininger, Grosz, Beckmann, Kandinsky, Moholy-Nagy, Naum Gabo, Paul Klee and more -- has come to Washington from Harvard's little-known Busch-Reisinger Museum of Germanic art. And it has arrived by a torturous route.

During the '30s, as the Third Reich was purging Germany of its best scientists, writers and artists, the nation's art, too, was being scattered in the wake of the Bildersturm, or painting storm. Museums were stripped of all art that Hitler found "degenerate" -- whatever that meant. Perhaps it involved too much feeling or social comment to suit him.

Photographs recorded the Fuhrer himself yukking it up with art collector Hermann Goering in 1937 at the now infamous exhibition of "Degenerate Art" organized by the Nazis in Munich before ridding the Reich of the works. It may well have been the greatest German Expressionist show of all time. Many of those works were subsequently sold off by agents or at auction in Switzerland. Others were smuggled out and hidden by German curators who watched in horror as their greatest 20th-century treasures evaporated before their eyes.

By 1937, some of the treasure was already in the Busch-Reisinger Museum (named for donor-brewer Adolphus Busch, it is often better remembered as the practice and concert hall of organist E. Power Biggs). Charles Kuhn, the young curator, had bought some sculpture by Barlach, Marcks, Kolbe and Lehmbruck and watercolors and drawings by Klee, Feininger, Kandinsky and Grosz -- all in an attempt to expand the collection beyond plaster casts as those of the 11th-century bronze doors as Hildesheim. But thereafter Kuhn began a rescue effort that would ultimately bring the museum its greatest treasures. Several are in the National Gallery show.

Foremost is the stunning "Self-Portrait in Tuxedo" by Max Beckmann, painted in 1927, in which he stares out intensely from the jaded world of the Weimar Republic. He seems aware but able to cope with the horrors that would soon force him to seek refuge in Holland and America. The painting was acquired in 1928 by the National Gallery in Berlin, where it became one of Beckmann's most celebrated works. What happened next is not clear, but in 1941 Kuhn bought the painting from a Swiss agent for $400.

Erich Heckel's haunting and haunted triptych, "To the Convalescent Woman," painted in 1913, is another major painting Kuhn acquired in 1950. It is a typical Expressionist work from the period just following the heyday of Die Brucke, a group of impoverished young German artists. They set themselves up in 1905 in a former Dresden butcher shop, and began trying to "bridge" (hence the name) various prevailing trends in art -- notably the cubist forms of Picasso and Braque and the color of Matisse and the Fauves. The striking results can be seen in other "degenerate" paintings here, among then Nolde's Fauvist-inspired "Mulatto Woman" and Kirchner's highly Cubistic portrait of the Expressionist writer Alfred Doblin.

This show, which fills three galleries on the mezzanine level, also has examples from the Blaue Reiter movement, and a particularly rich complement of works on paper by the artists involved with the Bauhaus School from 1919 until 1933, when Hitler closed it down. Founded by Walter Gropius, the Bauhaus artists' collective transformed modern art, design and architecture with its dictum "form follows function." Groplus went to head Harvard's School of Design in the '30s, and with his help the Bauhaus Archive has come to rest at the Busch. The geometrics of Kandinsky, Moholy-Nagy and Josef Albers share the final gallery with a whole wall of lyrical paintings on paper and silk by the endlessly inventive Swiss artist Paul Klee.

It is difficult to see now Klee's whimsy could have offended even Hitler, though there is less question in the stabbing lines of George Grosz and the monumental Beckmann triptych. "The Actors," an allegory of modern times.

Perhaps if the young Hitler had been admitted to the Vienna Academy of Art, which turned him down -- twice -- his taste might have been somewhat improved. The show continues through Sept. 1, and deserves a better informed commentary than it gets from the paltry handout offered free at the door.