The today highly controversial Theological Dictionary of the New Testament (TDNT) is one of German New Testament scholarship's most important twentieth century achievements. By tapping into previously unknown sources from several archives, this article demonstrates that the Marburg exegete Rudolf Bultmann (1884–1976) played a key role in the TDNT's planning and implementation from the outset. The first editor, Gerhard Kittel (1888–1948), deliberately engaged Bultmann, who was considered to be particularly »radical«, in order to unite the diverging theological positions in Germany for the work. Kittel and Bultmann first clarified open and controversial questions about the project among themselves and then presented their solutions to TDNT authors according to the principle of »qui tacet, assentire videtur«. In 1937 the collaboration fell into a deep crisis, which Bultmann was again instrumental in resolving.