If the Sontag/feminist fix on photography boosts Milton Meltzer's conscientious investigation of Dorothea Lange's life and work, so much the better: she was an instinctive, articulate photographer (who chose her metier before she clicked a shutter) and a major force in establishing the documentary tradition. As Meltzer lays out the evidence, Lange's penetrating Farm Security Administration pictures of migrants and sharecroppers follow naturally from her penchant for photographing people (not, even outside her commercial studio, "forms in nature"); the "desire to be useful" that, in the Depression, drew her into the streets; and a demanding, dissatisfied nature going back to childhood. "I had that sense very early of what was fine and what was mongrel, what was pure and what was corrupted in things, and in workmanship, and in cool, clean thought about something. I had that. I was aware of that." So she observed in the oral-history interviews that Meltzer astutely uses to project her personality and the character of her work. On the other hand, his log of her professional activities (and running battle with FSA boss Roy Stryker over final control of the image) and personal relations (especially the troubled course of her first marriage) is fuller than anyone but a S. Johnson or H. James warrants; and this lack of selectivity, added to earnest, colorless writing, robs the book of biographical drama. But en route, the San Francisco cultural scene comes alive, we see photography grow as "a tool for investigation," and assignments, exhibits, books mite intelligible, interesting shape. Then, out of the mass of minutiae, Lange will suddenly reappear--to say to visiting photographer Robert Frank, on her deathbed: "I just photographed you."