Tarzan and the Tarzan Twins followed by Tarzan, Lord of the Jungle
Despite the gap in when they were written and first published, the events of the two stories occur in the same time-frame. The opening passage of "Tarzan and the Tarzan Twins, with Jad-bal-ja, the Golden Lion" specifies that its events occur immediately after those of "The Tarzan Twins." In relation to other Tarzan stories, the two parts of the Tarzan Twins tale presumably fall between Tarzan and the Ant Men and Tarzan, Lord of the Jungle chronologically, as the initial part was published between these two novels. The second part confirms their placement in approximately this period, as it introduces a family that figures prominently in Tarzan and the Lost Empire, the next book after Tarzan, Lord of the Jungle; specifically, it features Tarzan's first meeting with Doctor Karl von Harben, with whom he is already acquainted in Empire. Because Twins is a children's book, however, it is customarily omitted from listings of the main Tarzan series. Thus Tarzan, Lord of the Jungle is generally considered the eleventh Tarzan book rather than Twins.