A handwritten letter from Martin Luther King to a female friend is to auction at Bonhams New York.
The lot is valued at $25,000-35,000 ahead of the June 16 Voices of the 20th Century sale.
The letter is addressed to Pauline Jackson, a close friend of King's for many years, and was sent from Albany jail in Georgia - where he was imprisoned briefly in the aftermath of a civil rights protest in 1962.
King discusses the condition of the jail and the political climate of the town. King was freed less than a month later after agreeing to halt the protests.
Bonhams explains: "King's presence certainly bolstered the scale of the existing protests, with probably 1,200 black residents spending time in jail...
"However, divisions among protest leaders (King's brief presence was resented by some student activists), tactical mistakes, the machinations of local police chief Laurie Pritchett, and the stubborn defense of white supremacy meant that the campaign was unable to force a citywide desegregation agreement in the short term.
"It was King's worst setback in the South."
The sale will also include a letter written by Lee Harvey Oswald to the head of the American Communist Party.
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