In the spanish dubbing of the movie, La Muerte is called "La Catrina", this is obviously "Posada's Catrina" a popular iconic skeletal lady that has become associated with the festivities of the Día de Muertos. Her main attribute is a gorgeous hat. In the movie, the modern Mexican icon (La Catrina) and the classic icon (Lady Death), are fused in a single role as the ancient Mayan goddess of death, ruling over one of the lands of the dead.
Video: The Book of Life
The original songs "I Love You Too Much" and "The Apology Song" were co-written by Paul Williams. According to director Jorge R. Gutiérrez, when he approached Williams, the composer assumed it was because he had co-written the Oscar-nominated "Rainbow Connection" for The Muppet Movie and was surprised to find that it was because of Gutierrez's love for Williams' rock musical Phantom of the Paradise.