Before writing "Elidor", Garner had seen a dinner service set which could be arranged to make pictures of either flowers or owls. Inspired by this design, he produced his fourth novel, "The Owl Service". The story was also heavily influenced by the Medieval Welsh tale of Math fab Mathonwy from, the "Mabinogion". "The Owl Service" was critically acclaimed, winning both the Carnegie Medal and Guardian Children's Fiction Prize. It also sparked discussions among critics as to whether Garner should properly be considered a children's writer, given that this book in particular was deemed equally suitable for an adult readership.