The language of John Steinbeck can be powerfully visual. In The Grapes of Wrath he wrote: "And the thought, the planning, the long staring silence that had gone out to the fields, went now to the roads, to the distance, to the West." If this sentence conjures up in your mind a black-and-white photograph of Dust Bowl migrants travelling the hard, gritty miles to California, chances are you''re remembering a photograph you''ve seen by Dorothea Lange.

Lange pioneered a new style of documentary photography in the 1930s, tightly focussing her camera on the subjects that would remain her enduring passion: ordinary people and their struggle for fairness and dignity. Now a new exhibit entitled "Human Documents," which opens this weekend at the Steinbeck Center in Salinas, offers Peninsula residents a rare occasion to see a wide selection of Lange''s art. The exhibit, organized by the Brigham Young University Museum of Art, draws from the substantial collection of Lange works belonging to the Oakland Museum of California; the Steinbeck Center is hosting its only West Coast appearance.

Born Dorothea Nutzhorn to German immigrant parents in 1895, Dorothea adopted her mother''s maiden name after her father abandoned the family. She left her home state of New Jersey at 19 and made her way to San Francisco, where she opened a portrait studio. There she met and married artist Maynard Dixon.

In the 1930s, Lange saw the need to take her camera to the streets of San Francisco, where the consequences of the Depression could be seen on every corner. Her first street photograph, "White Angel Breadline, San Francisco" (1933), is an early harbinger of the formal sophistication and empathetic approach for which she would become celebrated. The photo''s title evokes an orderly line, when in fact what Lange shows us borders on chaos: an uneasy mass of out-of-work men. Most of the mens'' faces are obscured by dark hats, lending sharp irony to the title, but Lange has centered the photo on one man. His grimly clasped hands remind us that prayer is often the daughter of despair. In the crook of his arms rests a tin cup--icon of the Depression--for coins, soup, coffee, alcohol, hope. It looks empty. Between the men and the viewer stands a thin fence made of pale 2x4 boards, a fragile barrier that warns the viewer how easy it might be to find oneself on its other, poorer, side.

Other images also highlight themes of exclusion in inventive ways. "San Francisco Street Demonstrators on Edge of Chinatown" (1934) is dominated not by the demonstrators of its title, but by a stern policeman who is there to control the crowd. The very shape Lange gives her photo thus replicates the marginalized experience of the socially dispossessed, forcing the viewer to look past the authority figure to see her true subject.

Several photos illustrate Lange''s interest in the expressive qualities of the human body. Lange suffered from polio as a child and walked with a limp throughout her life; in images such as "Migrant Mother," her signature work of the Depression, the hauntingly complex "Migrant Cotton Picker," and the tender "Hnads, Maynard and Dan Dixon," the human body is shown to be both soft and sculptural, a place of both heroism and heartbreak.

In 1935 Lange joined a team of other top-notch photographers (notably Walker Evans) to document for the California Federal Resettlement Administration (later the Farm Security Adminstration, or FSA) the dramatic westward migration of 300,000 desperate people. The fruits of Lange''s labors were published in 1939 (the same year Steinbeck published The Grapes of Wrath) in American Exodus, an innovative collaborative work that also featured the writing of her second husband, Paul Schuster Taylor. Long out of print, American Exodus (which was recently republished in a facsimile reproduction softcover edition), is a pioneering example of visual and written testimony interacting together to great effect.

Lange''s style invites a writerly perspective. Never mere "snapshots" or photographic "moments" stolen from the stream of time, her images appear rather to synthesize vast scenes, emotions, stories, causes. Look closely at any one of her images and vivid narratives dense with life will begin to unfold in your imagination.

Indeed, near the end of her own life, when a dehabilitating cancer had prevented her from engaging in the very physical work of photography, she turned to writing. In a recent phone interview, her son, Daniel Dixon, a writer who lives in Carmel, described his mother as a brilliant writer, someone who was able to channel a lifetime of visual insight and expertise into language. Dixon is currently putting together a collection of her writing that will show people yet another side of his mother''s artistry.

Lange''s art is endlessly challenging, often beautiful, often disturbing. Some revisionist critics have taken photographers like Lange and Walker Evans to task for manipulating their photos'' subjects in order to heighten a certain formal or narrative effect, thereby casting doubt on the photos'' documentary "authenticity." Lange''s celebrated "Migrant Mother," for example, features only two children, rather than the mother''s much larger actual brood, whose true size might well have alienated the sympathies of the middle-class audience Lange hoped to reach. The woman in the photo also became unhappy with "Migrant Mother" in her later years, claiming that "the most famous photograph in the world" had brought its subjects no monetary gain. Lange''s supporters have responded that in focusing the nation''s attention on its underclass, the photo has performed its own kind of social work, useful to all.

For what interested Lange most, as she put it, was not so much "the good photograph" as "the consequences of the photograph." In this, her artistic aims are well aligned with those of John Steinbeck, who always strove to see artistic dignity in the "junked lives," as he wrote in The Grapes of Wrath, that continue to fill the American landscape.