For one brief, ten-day period in his life Thomas Alva Edison kept a diary—a most surprising document, personal, fanciful, witty. His spelling and punctuation were erratic, but he wrote in the elegant calligraphy he had taught himself for transcribing Morse code. His wife had died in 1884, and after a lonely year Edison had fallen in love again, in the summer of 1885. He was thirty-eight years old at the time, had three children, and was already famous. It is not known exactly why he decided to keep a diary, why he stopped so abruptly, nor where he was when he began it. Probably he wrote it for Mina Miller—who was to become his second wife that fall—while he was visiting his friends the Gillilands, near Boston, although the first few pages refer to events in New Jersey. The whole diary will be published in facsimile next month by The Chatham Press, with an introduction by Kathleen McGuirk. A MERICAN H ERITAGE here presents, also in facsimile, the first entry of this charming document, for July 12, 1885.