This chapter introduces the following three, which survey the principal forms of Renaissance polyphony. Crucial to these forms is the relationship of music and text, which reveals considerable differences in approach during the period itself and relative to later periods from the Baroque to the present day. In unravelling these differences, the notion of genre and its pertinence to Renaissance music is critiqued in the light of recent scholarship, showing that Renaissance approaches to the concept of the musical work were also considerably different. Whilst this is a somewhat contentious issue, the points of tension uncovered here make sense of the evidence of primary sources (especially before the advent of print) concerning the re-purposing of polyphony outwith the context of its composition. The key difference from subsequent periods is that the notion of an ‘original’ would likely have had little pertinence to Renaissance musicians, and certainly none of the baggage that pertains to it in a later, Urtext-driven age. It also explains the relative porousness of the categories that later become studied under the heading of genre.