Through the Looking-Glass

Through the Looking-Glass was a book written by Lewis Carroll. Heather Lake and Annabel Lake read it together. (COMIC: The Broken Man)

Ace also read a copy of Through the Looking Glass, in the TARDIS. (PROSE: Cat's Cradle: Time's Crucible)

Behind the scenes
Though it may not be made clear in the DWU,  is the sequel to Alice in Wonderland.

The Eleventh Doctor quoted "The Walrus and the Carpenter", a poem in the novel, in The Rings of Akhaten when he explained to Merry Gejelh why she should not sacrifice herself to Akhaten.