The 1979 edition is the same as later editions, though the 1979 did have a darker cover. I suspect there may have been an even earlier edition as I owned a copy of this book at least as early as 1978, when I gave it to a friend--but it think it was years earlier. Without an exact year I can't find a record of it. Clearly though, on the larger book seller sites, there are plenty of copies of the 1979 edition in circulation.