The film is based on the novel by Willa Cather, though the link between this story and Cather's novel is thin at best. In their review of the film, the New York Times called the novel of A Lost Lady "a genuine American masterpiece," with a film that is "mediocre... by comparison". But according to A Life of Barbara Stanwyck: Steel True 1907-1940, other reviewers were not nearly so kind, and neither was Cather - who didn't want any further adaptations of her work. In fact, her will banned any further film adaptations of her works (along with publications of her letters. The ban on both was recently lifted by the Willa Cather Trust, as outlined in this New York Times report.) For someone who's work so focused on the American frontier, and the people who built it, seeing Cather's work made into a mere romantic triangle on rich people from the east must have been very hard for the author, and her fans, to stomach. While it is undeniably hard to successfully adapt a masterpiece of literature to the screen; script-wise, this adaptation doesn't even come close (and more to the point, doesn't really try). For more on Cather, visit Willa Cather: The Road is All from American Masters.
If you go into the film acknowledging that it's not Cather's book, it does have some enjoyable moments, mostly because of the excellent acting of the four leads. Stanwyck is, as always, exceptional as Marian, a woman who seems unable to select the right man. And Ricardo Cortez is wonderful; he gives Frank Ellison a subtle shadiness that is perfect for the character, and makes Frank a mirror image of the deceased Ned Montgomery - both men who are more interested in conquest than in love. Originally, the cast would have included Kay Francis and John Eldredge (see this AFI article. Eldredge's part is not specified. Probably, he was being considered for one of the roles that eventually went to Cortez or Talbot).
Lyle Talbot is excellent as Neil, the honorable man who loves Marian from afar, because of his regard for Daniel. Talbot provides a moral compass in the film, both in his relationship with the Forresters, and in his dislike of the relationship between Marian and Frank. Talbot had a remarkably long and noteworthy career, beginning almost with talkies (he had a lovely voice, in my opinion), and continuing until 1987 (he died at age 94, in 1996). When film work - primarily as the lead in B movies - began to elude him, he transitioned gracefully to television, appearing on episodes of shows such as The George Burns and Gracie Allen Show (where he had a recurring part), Bonanza, and Newhart. His film career was notable: we've already seen him in She Had to Say Yes (1933), Mandalay (1934), and No More Orchids (1934). His life was recently detailed by his daughter, Margaret Talbot, in her book The Entertainer: Movies, Magic and My Father’s Twentieth Century.
Finally, there is Frank Morgan who shines as Daniel Forrester. It's hard to make a character who is kind and gentle come across as anything but weak, but Morgan does it. He gives us a characterization that is pure in heart, but deep in his love for Marian and his desire to build a life with her. According to this TCM article, he was made up to look far older than his 44 years (though he never really looked young!) In a few more years, Morgan would be cast in the film that would probably gift him with eternal fame - The Wizard of Oz (1939), but he appeared in over 100 films, and was impressive in all of them.
We will leave you with a trailer from the film, where you can glimpse some of the lovely gowns designed by Orry-Kelly. While not a great film, it's certainly worth your time for the excellent acting that is on display; for plot, read the book instead: