Rachel Carson never married, nor did she ever show any signs of romantic interest in the opposite sex. After her move to Maine, however, she met a woman named Dorothy Freeman. It was the beginning of a passionate, but almost entirely secret, love affair. To the outside world, the two women were close friends. Freeman, in her 50s at the time, was married with children and strove to hide the nature of her relationship.
Carson and Freeman conducted much of their affair via letters. To safeguard their secret, they would often enclose two letters in a single envelope. One letter was for public consumption and could be read aloud to family and friends. The other was private and passionate and would have likely alerted a reader to the true nature of their relationship.
The private letters, it was agreed, were to be consigned to the "strong box," which was their nickname, or code word, for burning. They couldn't quite bring themselves to burn all the private letters, however, and in 1995 Freeman's granddaughter published the surviving ones in a book about the two women's relationship [source: NWHM].