The title of the book refers to the gates of horn and ivory described in both Homer's Odyssey and Virgil's Aeneid.

[1] David Langford, an author, editor and literary critic, points out that the multitude of impossible tasks placed before one of the main characters is based on the Mabinogion's incomplete tale of Culhwch and Olwen.

[2] Christian Huxley enters Ryhope wood on a search for the compelling mythago Guiwenneth and for a better understanding of his mother's suicide.

Echoing the tales of Culhwch and Olwen, Christian is assigned with completing many impossible tasks.

As Christian nears the end of his quest in the wood, he has an opportunity to enter the underworld (like Orpheus) and grapple with the suicide of his mother which has two very different manifestations, one true and one false.