This chapter deals with the features of fictional dialogue in a narrative genre that relies exclusively on auditory signs. In particular, it examines the case of the radio play. Rather than hypothesizing about necessary conditions and fixed features, the chapter will describe the conventions, constraints and affordances of the audiophonic dialogue. The specificity of audiophonic dialogues will be illustrated in an analysis of radiophonic pieces adapted from two novels by Harry Mulisch, namely The Stone Bridal Bed and The Discovery of Heaven. The comparison with the literary source text will allow us to better perceive the differences and similarities between the textual and the aural, between the literary and the radiophonic dialogue.