For someone so often in the Hollywood spotlight, Greta Garbo managed to stay impressively private, a skill that only added to her enigmatic allure. Now, Swann Auction Galleries is selling a set of over 65 personal letters that Garbo wrote to friend and fellow actress Salka Viertel, which shed light on what was really going on behind those famous blue eyes.

The letters, mostly written in English (though four are in German) and spanning from 1932 to 1973, paint a portrait of an anxious, exhausted woman who sometimes had misgivings about Hollywood and didn’t like solitude quite as much as her reputation implies.

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Around 1933, a pessimistic Garbo wrote to Viertel that she had returned from a European trip feeling tired, saying “I was so hounded, everything was so ugly that I no longer want to travel. And the terrible sense that Europe is dead. It’s dead.” Evidently, this disillusionment led her to object to filming 1933’s Queen Christina there. “Salka, I know I’m an impossible person, but I can’t make Christina in Europe. When you are as involved in film as I am, then you’ll understand,” she said. “I know that you’re hoping that Christina would be made in Europe—I’m very sorry Salka, but I’m in a state.”

A letter from 1935 suggests that Garbo harbored some negative feelings toward Irving Thalberg, who cast her in her first American film, 1926’s The Torrent, and produced several other high-profile films of hers, including 1926’s Flesh and the Devil, 1930’s Anna Christie, 1932’s Grand Hotel, and 1936’s Camille. In the letter, Garbo asked Viertel—a screenwriter, too—if she was involved in Camille: “And are you not doing anything on Camille? God help me if Thalberg does it alone … I could write [Louis B.] Mayer otherwise and perhaps he could let [David O.] Selznick do Camille.”

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In addition to the intriguing details about Hollywood people, places, and things, Garbo’s correspondence with Viertel is rife with references to the state of her own mental health. She frequently mentions feeling “tired,” “very off and on,” “so low,” and “very sad.” She also explains that “it is hard and sad to be alone, but sometimes it’s even more difficult to be with someone.”

Overall, the letters illustrate that Garbo seemed to be at a loss for how to make herself happy in her career, which may have factored into her departure from acting when she was in her mid-30s.

The collection, which is estimated to fetch between $40,000 and $60,000, hits the auction block on October 10.

Uncover more of the mystery behind the legendary actress with these facts.

[h/t Swann Auction Galleries]