87 volumes and 6 engagement diaries, all in very good condition. Includes the rare volume The Harlequin Tea Mystery! The Agatha Christie Mystery Collection (also known as the Agatha Christie Hardback Collection) is a book club set that was released by Bantam between 1983 to 2000. The volumes feature leatherette "Sussex blue" boards with gold lettered titles on the spine and a silhouette of Christie and the series title on the front cover.