After a strong May season in New York, the auction houses are looking for successful summer sales in London. And they have good reason, as previously reluctant sellers have been encouraged by recent results to consign closely held gems.

Also of note are two dance-themed works: Paul Klee’s whimsical and unusually large 26-by-22-inch oil "Tänzerin," 1932 (est. £2-3 million; $3.3-5 million), and a classic Edgar Degas scene of posed ballerinas executed in rich pink and yellow pastel and charcoal on tracing paper, "Avant l’entrée en scène (Deux danseuses)," circa 1888 (est. £4-6 million; $6.7-10 million). "It’s a tour de force," says Giovanna Bertazzoni, head of the London Imp/mod department, raving about the superb texture of the Degas.

In the Expressionist category, Auguste Macke’s exotic and color-charged watercolor and pencil "Im Bazar," 1914 (est. £600-800,000; $1-1.3 million), should appeal to those with a taste for the dramatic. Among the Surrealist works on offer are Max Ernst’s "2 holoëder sulfate silicate picastrate u. szillinge nach meiner wahl mit stäbchen," a formative 1920 collage on paper with gouache, ink, and pencil from a private Italian collection (est. £180-250,000; $300-418,000), and a 1963 René Magritte composition of ashen fruit seemingly carved from pockmarked stone, from his fantastical series "Souvenir de voyage" (£3.5- 4.5 million; $5.8-7.5 million).

The highlight of the June 22 Imp/mod evening sale at Sotheby’s is a rare and important "cityscape" painting by Egon Schiele, "Häuser mit bunter Wäsche, (Vorstadt II)," 1914. The small oil, depicting colorful clotheslines strung up in the yards of houses, carries a third-party guarantee and is being deaccessioned by the Leopold Museum, in Vienna, which bought it from the widow of Heinrich Böhler, who in turn acquired it from the artist in the year it was painted. It is estimated to fetch £22 million to £30 million ($36 million) in its first appearance at auction.

The house also has high hopes for a trio of modern works: Klee’s dense, kaleidoscopic "Stadtburg Kr." ("Town Castle Kr."), 1932, executed in oil and tempera on gesso and cardboard (est. £2- 3 million; $3.3-5 million), and Joan Miró’s ecstatic abstraction "Vipère exaspérée devant l’oiseau rouge," 1955, in oil and mixed media on cardboard (est. £2- 3 million; $3.3-5 million), both from the same Swiss consigner; and Magritte’s small 1955 gouache on paper "L’empire des lumières," a split day-and-night streetscape put up by the family of Madame Conrad Schlumberger, of the oil-and-gas fortune, who acquired it from the Greek dealer Alexander Iolas for a sum undoubtedly less than its current estimate of £800,000 to £1.2 million ($1.3-2 million). "These three works very much correspond to today’s taste," says Helena Newman, director of the Impressionist and modern department in London, "and they come to the market at a time when works by these artists are very sought after and have performed very well in recent sales." Magritte’s "Le maître d’école," also dated 1955, brought £2,505,250 ($4 million), a record for one of his gouaches, in the house’s February sale in London.

The contemporary season opens the following week, on June 27 at Phillips de Pury & Company. The house’s sale that evening will be headlined by Jean-Michel Basquiat’s bottle-cap-festooned "Self-Portrait," 1985 (est. £2-3 million; $3.3-5 million), and Wade Guyton’s giant inkjet-printed abstraction on linen "Untitled," 2007, the first of his "three-legged x" works to appear at auction (est. £150-250,000; $250-420,000). Phillips is also offering a complete set of 10 "Mao" color screenprints by Andy Warhol, 1972 (est. £300-500,000; $500-830,000).

The various-owners portion of the evening reflects renewed market confidence with Francis Bacon’s angst-filled "Crouching Nude," 1961, of a grimacing woman alone in a cell-like chamber with walls drenched in green (est. £7-9 million; $11.7- 15 million), as well as the largest work by Takashi Murakami to appear at auction since 2008, the giant six-panel silk, aluminum, and wood "Superflat Jelly Fish Eyes I," 2003 (est. £800,000-1.2 million; $1.3-2 million).

That the houses were able to coax sellers into placing top-rate material under the hammer speaks to the optimism surrounding the sales. "The market is strong," says Sotheby’s contemporary specialist Alexander Branczik. "It certainly feels like the dark days of 2009 are a distant memory." "London Sales Preview"

Fresh consignments from esteemed collections enrich the June 28 sale at Christie’s, which features a standout selection of works owned by Kay Saatchi, the ex-wife of the advertising magnate and art enthusiast Charles Saatchi and cocurator of some 30 shows at their gallery. "Kay Saatchi has been supporting young artists in the U.K. since the 1980s," says Francis Outred, head of postwar and contemporary art at Christie’s. "She played a key role in the YBA movement that completely transformed the contemporary-art landscape in Britain at the end of the 1990s."

Saatchi, who is moving to Los Angeles after 25 years in London, is parting with 31 works. Notable among them is Ron Mueck’s hyperrealistic, larger-than-life sculpture "Big Baby," 1996 (est. £800,000-1.2 million; $1.3-2 million), an arresting early piece (the first listed in his catalogue raisonné) that helped propel him to fame. The Saatchis met Mueck through his mother-in-law, the painter Paula Rego, whose five- foot-square canvas "Looking Back," 1987 (est. £600- 800,000; $1-1.3 million), a major work featuring three female figures and a dog, is also on offer, as are five exquisitely rendered, Surrealist-tinged studies from the 1940s by Lucian Freud. The house previewed these mixed-media drawings — which range from "Rabbit on a Chair," 1944 (est. £300-400,000; $500-668,000), on the top end to "Boy with a Pipe," 1943 (est. £80-120,000; $130-200,000), on the low end — in April in Moscow, the first exhibition of Freud in Russia, along with the artist’s important oil "Woman Smiling," 1958-59 (est. £3.5-4.5 million; $5.8-7.5 million), his only painting of Suzy Boyt, his longtime companion and mother of four of his children. Hailed by the critic Robert Hughes as a turning point in Freud’s career, the 28-by-22-inch portrait comes from a private European collection.

The following night Sotheby’s unveils rarities of postwar German art from the collection of Count Christian Duerckheim-Ketelhodt, who, according to Cheyenne Westphal, the head of contemporary art for Sotheby’s Europe, began buying in the early 1970s with the goal of establishing his own museum, which was never realized. Particularly deep in artists who moved from East to West Germany in the 1960s, such as Georg Baselitz, Sigmar Polke, and Gerhard Richter, his meticulously assembled trove of some 30 works is a time capsule of the era.

The biggest draw is Baselitz’s profane yet haunting "Grosse Nacht" ("The Big Night"), 1962-63 (est. £2-3 million; $3.3-5 million). When the painting, depicting a man masturbating, was exhibited in the artist’s first solo show at Michael Werner and Benjamin Katz’s West Berlin gallery, in 1963, authorities confiscated it on grounds of indecency. The house is trumpeting it as "the most important German work of art of the postwar period to come to the market." Another key early Baselitz, the existential "Das Idol" ("The Idol"), executed in 1964, a year after the Berlin Wall went up, is expected to fetch between £600,000 and £800,000 ($1-1.3 million).

Duerckheim is also selling a pair of Polkes: "Dschungel" ("Jungle"), 1967 (est. £3-4 million; $5-6.7 million), the largest of the late artist’s series of benday-dot meditations on the paradoxes of painting, and "Stadtbild II," 1968 (est. £2- 3 million; $3.3-5 million), an electric homage to the New York skyline. Joining the Capitalist Realist exemplars on the block are three more-accessible — and attractively priced — works by Richter: the color-chart painting "1024 Farben," 1974 (est. £1-1.5 million; $1.7- 2.5 million); "Telefonierender," 1965 (est. £2-3 million; $3.3- 5 million), a dizzily distorted photo-painting of an anonymous man speaking into a black handset; and "Schwestern ("Sisters")," 1967 (est. £1.2-1.8 million; $2-3 million), straddling the boundary between soft porn and propriety with its depiction of two scantily clad female models.

Christie’s starts the action on June 21 with an Impressionist and modern auction. The star of the sale, coming on the heels of Gagosian Gallery’s April "Amour Fou" exhibition in New York devoted to Picasso’s pictures of Marie-Thérèse Walter, is "Jeune fille endormie," 1935 (est. £9- 12 million; $15-20 million), in which the artist portrays his young muse and lover slumbering, head resting on her folded arms, in one of the ornate rooms of his romantic hideaway, the Château de Boisgeloup.

Portraits of Marie-Thérèse command among Picasso’s highest prices; at Christie’s in May 2010 the larger and more ambitious "Nude, Green Leaves, and Bust," 1932, fetched $106.5 million, a record for any artwork at auction. The University of Sydney consigned "Jeune fille endormie," which it received in 2010 from the estate of an anonymous American donor with express instructions to sell the work to benefit its scientific research programs. The picture had only one owner before the donor, the automotive heir Walter Chrysler, who acquired it in the ’30s and loaned it to the 1940 Picasso retrospective at the Museum of Modern Art in New York.