AbstractThe use of dialogue in scientific writing is for many reasons, as also L. Thorndike and R. Multhauf have mentioned, worth to investigate. This treatise concerning dialogues on pharmacy, chemistry, botany and also on medicine tries a classification and gives several interpretations of these important sources for the history of sciences, which in some disciplines were rather neglected in historiography for many reasons. One of these may be the difficulty to distinguish in this form of literature the poetical fiction from reality, the traditional topoi from contemporary controversies. The different aims of the dialogue, teaching, conversation, scientific discussion and also satirical intentions give the determination for the several literary forms of those colloquies, which have been important for progress and communication in sciences.