Reagan wrote the note to a friend in February of 1998, about four years after he mostly disappeared from public view following his announcement that he had Alzheimer's Disease. In the letter he told a friend, "Individuals like you give me the courage and inspiration to move forward, and with your prayers and God's grace, we'll know we will be able to face this long latest challenge." He adds a P.S: "I didn't write this with Nancy's help."
Bill Panagopulos, president of Alexander Autographs in Greenwich, Conn., will auction the letter next month. Panagopulos tells CBS News White House correspondent Peter Maer that Reagan's handwriting appears to be "very labored." Panagopulos says it could be a "one of a kind letter."
The autograph dealer believes the item could bring up to $9,000 at auction.
"Reagan has always been very strong ... Reagan was a popular president, even more popular nowadays with Republicans in power," Panagopulos said. "His letters and signed photographs and messages are very much in demand. He brings a very strong price."
Hear Peter Maer's interview with Bill Panagopulos
While letters and documents signed by Reagan are fairly common, "I don't think there could be more than a handful of letters from that period in his life."
It's quite jarring to see it, especially for those familiar with Reagan's "normal" handwriting," says Maer, who covered the White House during the Reagan administration.
"It's a very labored handwriting, done under great duress on his own part, and it shows me a great deal of bravery, strength and courage on his part," Panagopulos said. "He didn't have it typed, he hand-wrote it, which made it very special. Clearly these were special friends of his."
The cold war crusader whose sunny optimism made a nation believe it was "morning in America" died June 5, 2004, at the age of 93.
"He became an enduring symbol of our country," said President Bush at Reagan's funeral.
"He was the most plainly decent man you could ever hope to meet," added his son Ron.