In contrast to the codicology of text manuscripts or liturgical manuscripts, a systematic typology of manuscript sources of Renaissance music is lacking. This article is a first attempt to develop criteria which could be relevant for such a typology. Function and performance context are obviously among such criteria, but so are size, material, and decoration. By combining all textual and contextual parameters into a table and discussing the results, it becomes clear that no single criterion is sufficient to define a certain type of manuscript: institutional manuscripts can be big or small, lavish or simple; manuscripts whose primary function appears to be representation (rather than practical use) can range from enormous choirbooks to tiny chansonniers, from highly private to highly public objects; finally, there are books whose external appearance provides little or no clue as to what their function may have been. A Quellenkunde of the polyphonic manuscript has yet to be written.