A bittersweet memory of Christmas away from home; One Christmas, by Truman Capote. New York: Random House. 48 pp. $12.95.

Childhood memories are precious, especially ones of holiday celebrations, and we like to return to them. My first awareness of Truman Capote's book ''A Christmas Memory'' was through a televised version I saw about 15 years ago. It's the story of seven-year-old Truman, called ''Buddy'' then, and his best friend, Aunt Sook, an elderly distant cousin with whom he lived as a young child.

The relationship between Buddy and Aunt Sook and their ingenious holiday preparations made such an impression on me that I went out and bought the book to add to my own collection of Christmas stories. I have to admit that I still find it hard to read the book without shedding a few tears at the end.

''One Christmas'' is another heart-tugger, in which Capote recalls the Christmas when he was forced to travel by bus from Alabama to New Orleans to spend the holiday with his father. Like any six-year-old, Truman found it hard to leave home and his closest companion to be with a person he barely knew. In this recollection, Capote manages to recapture the feelings of the experience: his homesickness, his amazement at his father's lavish and unusual life style, and the abrupt yet bittersweet way in which his little boy's belief in Santa Claus ends.