The Agatha Christy Companion is comprehensive. It covers everything that Christie ever wrote and every play, movie and TV film based on her work. It's divided into six parts: 84 mysteries and thrillers, the 11 miscellaneous books (romances, autobiography, poetry, reminiscenses, and a children's book), the 21 plays, the 26 movies and the 18 TV films. The sixth part lists all the books and stories in alphabetical order, and lists the eleven major detectives and the novels and stories in which they appeared. There's a separate section for each of the 160 works, and each section includes a discussion of the book, play, movie or TV film; Christie's own comments; reviews, dedications, plot summaries, principal characters, English and American titles, adaptations, casts of plays and films; and other specific information.

Throughout the book there's material on what Christie was doing and what was happening to her at the time she was writing each work, and how she incorporated in her novels, stories, and plays events from her personal life and from her time.

The Agatha Christie Companion is as intellectually stimulating and superbly entertaining as a great Christy mystery.