MR. and Mrs. Leigh B. Block's collection of modern European paintings includes works by most of the major artists of the last 100 years. But it is most notable for its representation of the mature style of several artists, for its extensive sampling from the work of Cezanne, Braque, and Picasso, and for a few surprises.

The surprises include an uncharacteristic Fragonard. "Pirtrait of a Man as Don Quixote." Deviating from his customary pink skies, many-petticoated plastic girls and French delicacy, Fragonard provides here an eighteenth century antecedent for van Gogh's thick and quick brushstrokes, and sharp outlines.

Because of the large number of paintings in the exhibition, some limitation of focus is helpful in their evaluation. One approach is to concentrate on the Blocks' very rich collection of portraits, including Degas' distant "Young Man with a Hat," Seurat's study for a "Woman Powdering Herself," the famous Matisse "The Young Sailor" (version two) and the even better-known van Gogh "Self-Portrait," showing his bandaged ear. In addition, there are three sensitive Vuillards, one a "Portrait of the Artist's Mother" in a style set between the thick modelling of Manet and the pointillist inheritance of Impressionism, the other a radical self-portrait which gains depth by the luxtaposition of flat planes of color.

THE collection's Picassos include oils, charcoal drawings and an inkwash. "Picador with Figures" which is monumental and timeless. Although the Picassos are well worth seeing, it is in the work of his contemporary, the late Georges Braque (1882-1963) that the growth of a master can be more fully traced.

Braque's versatility as a painter is legendary and a wide range of his development in oils can be seen here. A few examples include a 1906 land-scape very much like Fauvist work, particularly reminiscent of Vlaminck. Later, in 1911, at the height of the Cubist period, Braque painted the "Still Life with Banderilas," one of a series of muted-tone exercises almost indistinguishable from Picassos of the same period. Three still lifes, one of 1929, another 1939, and of 1941 show his developing interest. The first includes a lemon painted to look flat, while on an adjacent goblet, whose three-dimensionality is complicated by its transparency, is depicted by juxtaposed planes of light and dark. Here Braque is consciously playing with the eve and its perceptions of boundary, a theme in his work well traceable through the Block holdings.

The 1941-1942 "Still Life with Grapes and Bananas" is a rich tapestry of color and form, that appears tactile, and that toys with depth by distorting perspective. The two largest Braques in the collection are masterworks. The first, a "Still Life with Fruit and Mandolin," overlays lavendar and greys; its design breaks down objects into pattern and builds up pattern just enough to suggest objects. The distinctions between foreground and background are distorted, objects merge with and emerge from their surroundings, while color and pattern interact in such a way that the idea of color as attached to form breaks down.

In "The Large Billiard Table" color and pattern tie the composition together, while the changing point of view from two to three dimensionality pulls it apart. For all the brilliance of these paintings, it is "Wheatfield"--a small work compared to the others--which is the most eccentric, and the most subtle and fascinating in its daring use of materials and sophisticated intentions.

The Block collection is far too rich for only one visit. In addition to the works described, there are sensitive flower paintings by Piet Mondriaan, known for his geometrical constructions, drawings by Matisse, and a powerful portraval of Christ and the Apostles by Rouault. In short, if the collection consisted of only a small fraction of the work now on exhibit, it would still well merit a visit.