The Longer Ending of the Gospel of Mark (Mark 16:9-20) was appended to the Gospel of Mark in the first half of the second century. James A. Kelhoffer explores this passage’s distinct witness to the use of gospel traditions and the development of Christian thought. Concerning the origin of this passage, he argues that a single author made use of the New Testament Gospels in forging a more satisfactory ending to Mark. He studies the passage’s sometimes innovative literary forms as well. Also of interest is the passage’s claim that the ascended Lord will help those who believe to perform miraculous signs - casting out demons, speaking in new languages, picking up snakes, drinking poison with impunity and healing the sick - when they preach the gospel (verses 17-18, 20). This expectation is compared with portraits of miracles, especially in the context of mission, in the New Testament, various apocryphal acts and Christian apologists of the second and third centuries. In the two final chapters the author interprets the signs of picking up snakes (verse 18a) and drinking a deadly substance with impunity (verse 18b) in their history of religions contexts. An Epilogue summarizes the findings of this study and explores what can be ascertained about the otherwise unknown Christian author of Mark 16:9-20.