NEW YORK - Some of the most celebrated works by Norman Rockwell, one of America's best-known artists, will be offered at Sotheby's American Art auction on 4 December 2013.

The seven paintings by Norman Rockwell from the family of Kenneth J. Stuart, Sr, include one masterpiece as well as several completed works and color studies. The artist's longtime friend, Mr. Stuart was art editor at the Saturday Evening Post, the publication that became nearly synonymous with Rockwell's influential vision of American life. Rockwell's personal and professional relationship with Mr. Stuart coincided with the artists most productive and creative period.

Read below for details on two key lots.

Norman Rockwell’s Saying Grace, cover illustration for the Saturday Evening Post, 24 November 1951, estimate $15–20 million.

Named Rockwell's most popular cover years after it appeared on the 1951 Thanksgiving issue of the Saturday Evening Post, Rockwell’s Saying Grace was based on a reader's idea submitted to the artist about seeing a Mennonite family praying in a restaurant. Rockwell depicted several of his favorite models, including his son Jarvis, seated at the table with his back to the window next to Rockwell's studio apprentice Don Winslow.

Norman Rockwell’s The Gossips, cover illustration for the Saturday Evening Post, 6 March 1948, estimate $6–9 million.

Rockwell depicted the theme of gossip several times in his career. In his movie-montage-like work The Gossips, the artist uses his Arlington, Vermont, neighbors as models, as well as his wife Mary (second from left and third row from top) and himself (bottom row right, in a hat).

Select works will be on display at Sotheby’s Los Angeles
 25 and 26 September, at Hong Kong Convention & Exhibition Centre 3 to 7 October and at Sotheby’s New York 
1 to 13 November
 and 29 November to 3 December.