I have just finished a terrific book, Kathryn Stockett's THE HELP. Set in the early 1960's in Mississippi, the book's protagonist is a young white woman who wants to be a writer. As the civil rights movement heats up the South, she collects interviews with black maids on what it's been like to work for white families. Amid the beatings that accompany voter registration and the maids' fear of being fired for speaking out, the entire project is conducted in secret.
The novel is multiple first person, from three points of view: the white woman and two black maids. Stockett has written that much is based on memories of her own childhood in Mississippi and of the maid that virtually raised her, Demetria. For the maids in the book, Stockett writes in a mild dialect, misspelling a few words and using expletives and diction that, she says, were common to Demetria.
When I finish a book, I like to read the customer reviews on amazon.com. Most of these were highly laudatory, but a few took Stockett to task for attempting to write from the POV of black characters; a few criticized her reproduction of dialect at that time and place; a few objected to how "saintly" all the black characters seemed and a few to the ones that were not so saintly. This is the kind of thing that almost always comes up when I teach writing: Can an author effectively write from the POV of a character of a different race, gender, cultural background, nationality?
My own answer is yes, IF you have enough first-hand observations of the milieu plus some sympathy for it. I, for instance, could never write about Mississippi in the '60's; I was not there, did not know its people, and would get a million details wrong. Stockett was there. She wasn't inside a black woman's head, but she knew Demetria intimately and I trust her portrayal. There is no axe to grind in this book. Both the black POV characters, Aibilene and Minny, feel real and multi-dimensional (and Minny is not saintly).
What about research as sufficient guide? Obviously that has to suffice for historical novels, or otherwise we would not have BLACKOUT (Connie Willis), THE OTHER BOLEYN GIRL (Philippa Gregory) or ATONEMENT (Ian McEwan). Writers cannot visit the past (and where is a good used time machine when you need one?) Even Octavia Butler in KINDRED was writing a character of her own race but outside her time period (ante-bellum South), and so some of KINDRED'S characters must be taken partly on faith.
And for me that's the bottom line -- how much faith do you have in this author to insert himself into a mind not his own and so become someone other than himself? I posit that you better have some faith when you read or we're all limited to autobiographies. If, as you read on, that faith seems justified, then the writer was certainly correct to "write the other." It's not "cultural appropriation" -- it's good fiction.