Book excerpt: This publication is a kind of workbook or manual. It is not a music history, nor is it a technical, musicological book. It is rather a book about materials ? musical materials and their relation to other artistic materials. It is not a book for professionals or specialists but for those who like to explore the capacities and possibilities of artistic materials. However, it never talks about them in a technical way. This book is instead about love and desire for old repertoires, and especially for polyphony, attempting to retrace its shape: the initial desire that makes one want to perform this music.