In New York on 20 May there is a rare opportunity to buy a masterpiece from Picasso's Rose Period. A world record price is predicted

Apollo, May, 2004 by Susan Moore

Superlatives are a saleroom speciality. Sometimes they are even justified. In the case of the group of paintings offered from the collection of the late Mr and Mrs John 'Jock' Hay Whitney in New York on 5 May, however, Sotheby's publicity sounds positively restrained. For what goes under the hammer next week is essentially the final offering from what was one of the greatest collections of Impressionist and Modern art of the twentieth century. Moreover, its centrepiece, Picasso's Garcon a la pipe, must rank among the most delectable paintings in private hands.

Garcon a la pipe, also known as Le jeune apprenti, was painted in 1905 when Picasso was twenty four and living at the Bateau Lavoir in Montmartre, so-called because of its resemblance to a Seine washing barge. His model was probably the young boy known as 'P'tit Louis', who frequented the place together with assorted harlequins, acrobats and strolling players, and who used to watch Picasso work. According to Andre Salmon, in La jeune peinture francaise of 1912, Picasso returned to his studio one night and took up this canvas of the boy in his blue workman's overalls that he had abandoned a month before and, in a moment of 'sublime whim', garlanded the little apprentice with roses and framed him with bouquets. Suddenly the image was transformed into something enigmatic, haunting and poetic.

Despite the best efforts of scholars, the artist's early work has always been the most accessible and appealing, not least the melancholic beauty peculiar to his rose period. Garcon a la pipe is one of the most important of the artist's early works ever to come to auction. More significantly, it is one of only a handful of blue or rose period paintings remaining in private hands and arguably one of the best two or three. Anyone wanting a great early work to anchor their collection of Picassos or of modern art would not be advised to wait for the next one. But how do you value a twentieth-century icon?

According to Charles Moffett, Co-Director of Impressionist and Modern Art at Sotheby's, the painting is 'up there with Dr Gachet'. Van Gogh's portrait of his doctor which was sold for $82.5 million in 1990; 'there is no knowing how far a painting like this can go'. Garcon a la pipe comes to the block with an estimate of $70m, and the bets are on as to whether it will end Dr Gachet's fifteen-year reign as the most expensive painting ever sold at auction. 'Price', contends Mr Moffett, 'won't be an issue here. The picture will be the issue. The demand at the top end of the market continues to be very strong. I won't say it defies gravity, but almost'. Price may not be an issue to the five to ten private collectors who may seriously consider buying this picture, but it is for Sotheby's, which has 'guaranteed' its sale, ensuring the vendors a specific sum whether or not the painting sells.

Certainly in the past the market has embraced Whitney pictures with open arms. In 1990, Renoir's celebrated Au moulin de la galette almost doubled expectations to fetch $78.1m. At the $128m sale of Impressionist and Modern art from the Whitney estate in 1999, their Cezanne still life similarly soared, realising $60.5m. George Bellows's Polo crowd, part of another tranche of museum gifts bequeathed after Mrs Whitney's death in 1998 but subsequently deaceessioned by the Museum of Modern Art because it did not fail into its remit, defied its $10m estimate to sell for $27.5m. During the course of their long collecting career, the Whitneys gave perhaps $300m of Impressionist, Modern and American paintings--among them Van Goghs, Cezannes and a Toulouse-Lautrec--to the National Gallery of Art (Washington), MoMA (New York) and Yale University (New Haven). It was their intention that their Long Island home, Greentree, would be preserved and used as an international meeting place to further the causes of peace and human rights, and it is the Greentree Foundation, the recipient of most of Mrs Whitney's personal property, which is selling this last group of forty four paintings, together with furniture and other works of art on 18 May.

What else can a quality-starved market expect to find? Taking a bow is a rare Manet racing painting, Courses au Bois de Boulogne, not so much a sporting picture as a bold and stylistically daring scene of modern life, the blurry, faceless crowd propped up in their carriages against a vivid aquamarine field (estimate $20m $30m). Degas is also represented by two racing pictures (estimate $5m-$7m apiece), and Munnings by four, including The Rod Prince Mare ($4m-$6m).

The Greentree Stud was another Whitney passion and testament to the Midas touch of this gilded couple. In terms of buying art, certainly, they barely put a foot wrong. Of course, Mr Whitney's long association with MoMA and the National Gallery gave him access to the advice of some of the most distinguished scholars of the day, but many rich men have bought badly on sound advice. And Whitney was a rich man, inheriting a fortune and going on to create another by founding the first venture capital company in the US and the Whitney Communications Corporation.