James Herbert Brennan (5 July 1940 – 1 January 2024) was an Irish lecturer and the author of over 100 fiction and non-fiction books for adults, teens and children, as well as several role-playing games.

Applecline also pointed out that Man, Myth, & Magic was "one of the earliest RPGs to provide truly serialized adventures" and that "Man, Myth & Magic went further, providing tighter connections between adventures, and even cliffhangers at the end of each supplement.

[3]: 165 In 2003, using the pen name "Herbie Brennan", he created a fantasy action novel for young adults titled Faerie Wars, and it proved very popular, reaching number 4 on the New York Times best seller list for paperback children's books.

[7] In all, Brennan wrote five books in The Faerie Wars Chronicles, which sold a combined 7.5 million copies.

[6] Brennan also authored numerous other books covering many subjects including history, the occult, New Age, self-improvement, parapsychology, and several romance novels.

[8] In 1998 he published Martian Genesis an ancient astronaut book which claimed the human race is of extraterrestrial origin.

The book purports to instruct children on how to become a wizard; it discusses crafts such as making a wand, and includes astrological references throughout.

According to the biographical note on the back cover, Rumstuckle "joined the Wizards' Guild in 1514 and became its youngest president ever seventy-eight years later, a post he holds to this day."