He was considered a loner and a misanthrope, but J.D. Salinger, who died recently, also had a warm and affectionate side. Previously undiscovered letters he wrote to an old army friend, which have been seen by SPIEGEL ONLINE, offer fascinating insights into the private life of the reclusive US author.

The letter is short and laconic. Six paragraphs, neatly typed, signed by hand. The sender writes that he misses the recipient, and he reports on the things that happened during his absence: Two fellow soldiers were wounded, a third soldier was given a military discharge, and another -- described as a "nice guy" -- is in Cuba. The writer's tone wavers between sarcasm and self-pity. He seems depressed, but he also mentions the possibility of having a drink with the recipient soon.

It is a letter from one friend to another, and yet it is so much more. The document, dated April 25, 1945, is a slice of contemporary and literary history.

Not just because it was written by a young GI on the German front, shortly before the end of World War II. Or because the "nice guy," as the writer elaborates in the course of the letter, was literary giant Ernest Hemingway.

In fact, the letter's importance stems from the identity of its author: Jerome D. Salinger, the notoriously reclusive American writer who died in January, at the age of 91. His first and only novel, "The Catcher in the Rye," published in 1951, shaped the attitudes of generations, but Salinger went into seclusion shortly afterwards and did not publish anything at all after 1965. Since his death, researchers have been grasping at practically every word that might have come from his pen.