A book with a collection of all of Agatha Christie's Miss Marple stories is recognised by the Guinness World Records as the thickest book published. More than a foot thick, the 4,032-pages book weighs 8.04kg, and has 12 novels and 20 short stories. Agatha Christie, the best-selling novelist of all time, was born 126 years ago on September 15, 1890.