To this day it has never been confirmed who wrote 003½: The Adventures of James Bond Junior, although many authors have been named as possibilities such as Roald Dahl and Kingsley Amis. Amis is usually seen as completely bogus since a year later he released Colonel Sun under the pseudonym Robert Markham, however, unlike R. D. Mascott, Amis's authoring of Colonel Sun was never a secret. Amis's writing style is also not similar to Mascott. Roald Dahl on the other hand does share some similarities specifically with one book he wrote in 1975, Danny, the Champion of the World. Coincidentally, in 1967, Roald Dahl completed the screenplay for You Only Live Twice for EON Productions, the same year 003½: The Adventures of James Bond Junior was published. Although there is evidence to suggest Dahl may have written 003½, there is equally as much evidence to suggest he didn't.
One author that has recently been identified as a possibility is Arthur Calder-Marshall who wrote a number of similar books especially in style and his descriptions of characters and environments in his books The Magic of My Youth (1951) and The Scarlet Boy (1961). It has also been suggested that the initials R. D. are a play on the name Arthur, which is typically shortened to Artie. Other writers that have been named as possibilities but tend to be rejected, include Peter Fleming (Ian's brother) and Nichol Fleming (Peter Fleming's son and Ian's nephew).