Before the world knew her as Marilyn Monroe, Norma Jeane Baker so captivated photographer Andre de Dienes at her first modeling assignment that he later recorded their meeting in his diary: "An earthly sexy-looking angel! Sent expressly to me!" De Dienes simultaneously captured the innocent exuberance and seductiveness of the young model in a series of photos that day in 1949 as she frolicked on a Long Island beach.

They are among more than 100 Monroe images being offered for sale in three sessions on Dec. 16-17 at Christie's auction house. They are expected to bring from $811,000 to $1.1 million.

The photographs represent a chronicle of Monroe's short life, from obscurity to Hollywood sex goddess. They capture her in all her manifestations — playful, sexy, innocent, insecure and anguished — as recorded by some of the biggest names in photography, including Tom Kelley, Richard Avedon, Bert Stern, Gary Winogrand, Elliott Erwitt and Cornell Capa.

A set of four portraits from the Tobey Beach series, showing Monroe with long, curly tresses and her trademark winning smile, is estimated to sell for $7,000 to $9,000.

"She is one of the most iconic figures in the history of American culture of the past 100 years," said Josh Holdeman, head of Christie's 20th century art.

Among other highlights is a group of photos known as the "Last Sitting" and taken by Stern for Vogue in 1962, just weeks before Monroe's death at 36.

The eight-page feature was shot during three long sessions at the Hotel Bel-Air in Beverly Hills. As the issue was going to press, Vogue learned that the actress had died. An emergency meeting was called and it was decided that the photo layout should run just as planned — as a memorial tribute to Monroe.

Fifty-nine key images from the shoot — including an uncharacteristically forlorn-looking Monroe in a black dress that conceals her body — are estimated to bring $100,000 to $150,000.

A 1957 portrait of a crestfallen-looking Monroe in black halter dress — in which photographer Richard Avedon turned "the subject from a star into a mere mortal" — is estimated to fetch the sale's highest price for a single photo, up to $35,000, Christie's said.

Avedon "banished every trace of the erotic charm and effervescence for which the actress was celebrated. ... Behind the beautiful face, her spirits sag as gravely as the body beneath the sequined dress," the auction house said.

Christie's said the sale represents the largest collection of Monroe photos to come on the market. Many of the images were featured in the "I Wanna Be Loved By You" Monroe exhibition at the Brooklyn Museum of Art in 2004.

New York collectors Leon and Michaela Constantiner are selling the photos plus 250 other images representing fashion, glamour and celebrities by such art-world stars as Andy Warhol, Helmut Newton, Irving Penn and Robert Mapplethrope.

The collection also has an unusually large number of sexually explicit prints as well as nude photos of actors and models such as Kate Moss, Patti Hansen, Charlotte Rampling and Nastassja Kinski.

Buyers from around the world have expressed interest in the Constantiner collection, one of the largest of its kind, said Holdeman.

"For them to have embarked on a journey far before it became in the public eye critically important, it's incredibly prescient and ambitious," Holdeman said.