The film starred Meryl Streep and Shirley MacLaine, with Dennis Quaid, Gene Hackman, Richard Dreyfuss, Rob Reiner, Mary Wickes, Conrad Bain, Annette Bening, Simon Callow, Gary Morton, and CCH Pounder.
On transforming the book into a movie script, director Mike Nichols explained, "For quite a long time we pushed pieces around, but then we went with the central story of a mother passing the baton to her daughter."
The last three sections are traditional third-person narrative. As one reviewer notes, this progression from first to third-person narrative shows how disconnected Suzanne is from herself, now that she's not on drugs.
The book ends on a bittersweet note: she knows she has a good life, but doesn't trust it.
Unlike the movie, most of the conflict in the book is internal, as Suzanne is learning to handle her life without the prop of drugs. Suzanne's mother appears in very few scenes, while Suzanne is in rehab:
After being discharged from a rehab center, she returns to work. According to her agent, she can only be cleared by the insurance people if she lives with "a responsible party", such as her famous mother, Doris Mann (played by MacLaine), a bright star of the past whose wine consumption seems alcoholic to Vale. This is not easy for Vale, as she struggled for years to get away from her mother. Things are not made any better when Mann, a brassy, upstaging, competitive woman, who continuously changes the subject to herself, gives her daughter loaded advice and insinuating value judgments while treating her like a child.
Vale's maternal grandpa (played by Bain) is a quiet man, while her down-to-earth, plainspoken grandma (played by Wickes) is a wisecracking and crotchety old woman. It occurs to Vale that not only do daughters have mothers, mothers do too.
Vale also reenters the world of moviemaking, including visits from the head of the studio, Joe Pierce (played by Reiner) about drug testing. She also deals with comments on her imperfect body and her performance onscreen.
Eventually, Jack Faulkner (played by Dennis Quaid) re-enters Suzanne's life. At first she does not realize that Jack is the one who drove her to the hospital during her overdose. She reluctantly agrees to go out with Jack. When Jack arrives at Doris' home to pick Suzanne, Doris' flirtation almost goes a bit too far, which sets up the idea that Suzanne constantly feel as though she is in competition with her own mother.
Jack and Suzanne share a passionate first date where Jack professes eternal and intense love for her and Suzanne falls for it. After a very late evening out, Suzanne returns home to find Doris waiting up for her. "What if you had been doing drugs or something?," Doris asks. Suzanne actually questions Doris' own drinking. The two have a quiet, but pointed exchange.
Upon hearing an indiscreet comment about Jack's actions from her movie co-star, Suzanne catches up with bit-player Evelyn Ames (Annette Bening in one of her earliest breakout roles) and finds that Jack has been sleeping with Evelyn at the same time as Suzanne. She drives to Jack's place directly from the studio, all the while still in her police costume. After confronting him with the news she's learned from Evelyn, the two fight and Suzanne decides to storm out. As she gets into her car, Jack infers that she was much more interesting when she was loaded and insults a film he earlier told her was his favorite. She begins shooting at him with a gun....but it's merely a prop gun from the movie set. "Relax, they're blanks."
When she gets home from Jack's, Suzanne is informed by Doris that her business manager has run off with all her money. A bigger fight ensues between mother and daughter and Suzanne storms out. Doris misses that Suzanne merely said she was going to a looping session. The looping session proves fruitful for Suzanne, when her director (Gene Hackman) tells her that as soon as she gets clean, he has another job for her.
Suzanne arrives home to discover that Mann tore off looking for her and, due to too much alcohol, crashed her car into a tree. When Suzanne greets her mother at the hospital, Doris is not wearing her wig and practically bald. Suzanne's grandparents are in the room as well, and Grandma is being pretty bossy with daughter Doris. Suzanne pushes Grandma out of the room and mother and daughter have a calmer heart to heart while Suzanne does Doris' makeup and adds a scarf to her head.
Once properly made up ("We're designed more for public than for private," Suzanne quips), Doris musters her courage and faces the press over her accident. Vale then sees Dr. Frankenthal (Dreyfuss), who pumped her stomach. He asks if she will go out with him to a movie. Vale replies, "Sure, we could go see Valley of the Dolls." In seriousness, Vale tells the good doctor that she is not ready to date yet and needs more time for her recovery. The doc says he'll wait.
The film ends with Suzanne beginning a comeback with a music video, as her mother watches from above the set.
Postcards from the Edge gives a reasonable perspective of life behind the glamour, as the two powerful lead actresses explore their relationship as mother and daughter together. Vale admits to feeling inferior to her mother and explains how Mann's behavior affected her childhood, while Mann admits to feeling old and a bit jealous of her daughter's success.
In Fisher's DVD commentary, she notes that Debbie Reynolds wanted to play the part of Doris Mann, but Nichols cast MacLaine instead.
Director Mike Nichols asserted, "Carrie doesn't draw on her life any more than Flaubert did. It's just that his life wasn't so well known."