The last few days have brought an onslaught of announcements from the big auctions houses about their May sales, which are already looking to be some of the all-time biggest art auctions. Hundreds of millions of dollars worth of material will be offered during the Impressionist and modern or post-war and contemporary art auctions in the first and second weeks of May, respectively, with iconic works by hallowed artists like Edvard Munch, Paul Cézanne, Andy Warhol, and Francis Bacon, many of which are fresh to market. The month is set to be an intense one, either a series of dazzling highlights or spectacular flops.

Here, ARTINFO rounds up information on some of the most coveted items, and why they are attracting so much attention (to see some of the commentary in illustrated slide show format, click here).

IMPRESSIONIST AND MODERN ART – CHRISTIE'S

Work: Paul Cézanne – Watercolor "Study for the Card Players" (1892-96)
Estimate: $15-20 million
Importance: This work is both new-to-market and tied to one of 2011's most famous sales — the $250 million purchase of the original "Card Players" painting (for which this work is a study) by the Al Thani family of Qatar. According to Christie's, the watercolor was last seen in 1953, and was rediscovered in the spring in the private collection of Dr. Heinz F. Eichenwald of Texas.

Work: Henri Matisse – "Les Pivoines" (1907)
Estimate: $8-12 million
Importance: From Matisse's Fauvist period, the work is a still-life with vivid colors depicting a pot of flowers. It was painted two years after Matisse and André Derain began working with bright and bold forms and colors. In 2011, a Fauvist work by Matisse's contemporary, Maurice de Vlamnick, sold for $22.5 million at Christie's New York.

Other works to look out for: Pablo Picasso's "Deux nus couches" (1968), est. $8-12 million; Alberto Giacometti's "Buste de Diego" (1957), est. $8-12 million; Claude Monet's  "Les demoiselles de Giverny" (1984), est. $9-12 million); and Henry Moore's "Reclining figure" (1956), est. $4-6 million.

IMPRESSIONIST AND MODERN ART – SOTHEBY'S

Work: Salvador Dalí – "Printemps nécrophilique" (1936)
Estimate: $8-12 million
Importance: Surrealism is having a moment in the art market. At last November's anemic Impressionist and modern art sale at Christie's, Max Ernst's Surrealist "The Stolen Mirror" was the auction's saving grace, attracting excited bids and eventually a $16.1 million price-tag (est. $4-6 million).  This particular work, shows two faceless figures in a dream-like composition, a seemingly endless expanse of sand and sky. The flower-headed woman in the work is a character that appears in many of Dalí's works.

Work: Edvard Munch – "The Scream" (1895)
Estimate: In excess of $80 million
Importance: The "Scream" image is one of the most well-known in art history — even the popular television show "The Simpsons" has appropriated the work — and is thus likely to draw the interest of the world's wealthiest and most powerful art collectors. This version is the only one of the four completed by the artists to remain in private hands, making it even more rare.  

Other works to look out for: Paul Delvaux's "Le canapé bleu," est. $3.5-5 million; Max Ernst's "Leonora in the Morning Light," est. $3-5 million.

POST-WAR AND CONTEMPORARY ART – CHRISTIE'S

Work: Yves Klein – "FC 1 (Fire-Color 1)" (1961)
Estimate: $30-40 million
Importance: Klein completed this work using a blowtorch and models as "brushes" just a few weeks before his death in 1962. It features both his signature "International Klein Blue" color and anthropometric elements. Klein works are rare because he died so young (at the age of 34) and worked as an artist for only seven years. If it hammers down within estimates it will be a record for the artist at auction and put Klein in the top-tier of blue-chip contemporary artists price-wise. The auction house claims that it is the most important work by Klein ever to be offered at auction, although ARTINFO has no third-party sourcing to back that up.

Work: Mark Rothko – "Orange, Red, Yellow" (1961)
Estimate: $35-45 million
Importance: Christie's announced this work would be sold at the post-war and contemporary sale as part of the David Pincus collection, which includes a bevy of important Abstract Expressionist works by the likes of Rothko, Willem de Kooning, Jackson Pollock, Barnett Newman, and a rare Clyfford Still. In this work, blocks of red, orange, and yellow seem to float above a brown background in the artist's signature style. Quality Rothkos can go for high-eight figures (one from the collection of David Rockefeller sold for over $70 million in 2007), so it is not terribly surprising to see the auction house estimating around $40 million.

Other works to look out for: Pollock's "No. 28, 1951," est. $20-30 million; Newman's "Onement V" (1952), est. $10-15 million, and de Kooning's "Untitled I" (1980), est. $9-12 million.

CONTEMPORARY ART – SOTHEBY'S

Work: Roy Lichtenstein – "Sleeping Girl" (1964)
Estimate: $30-40 million
Importance: After Lichtenstein's "I Can See the Whole Room... And There's Nobody In It!" (1961) fetched $43 million last November, work by the pop artist featuring his iconic cartoon-like characters are likely to be in high demand. While this pieces does not have one of Lichtenstein's signature speech bubbles, it has been off the market almost 50 years, since 1964, and is one of the highest-quality works done by the artist in his series of single-figure works featuring blonde women.

Work: Andy Warhol – "Double Elvis" (1963)
Estimate: $30-50 million
Importance: The work was included in Warhol's dedicated Elvis show at Los Angeles's Ferus Gallery in 1963, a seminal moment in the Pop artist's career. The cowboy-like Elvis is a complement to Warhol's feminine and flirty Marilyns and Jackies. Nine of the 22 works created in the series are currently in museum collections, and this is the first to come to market since 1995.

Work: Francis Bacon – "Figure Writing Reflected In Mirror" (1977)
Estimate: $30-40 million
Importance: Just announced Thursday, this is one of the British painter's most iconic works. It was shown in 1977 at Galerie Claude Bernard in Paris alongside "Triptych" (1976), which was purchased by Russian billionaire Roman Abramovich for $86.3 million in 2008 — the record for most expensive contemporary work of art sold at auction. In the painting, a figure sits in his underwear at a desk, writing in front of a mirror with Bacon's signature dark palette and smudged paint.