This work on Gregorian modes is intended for professional and amateur musicians. It is accessible, detailed, lively and complete. It is written from a musical point of view, but medieval documents were also used and the results of this research can be understood by non-specialist readers.
Gregorian composition devices are made clearer. Organization, structures,… all is explained and detailed. There is also a symbolic explanation of the different modes. It might be a way of understanding how much initiatory the Gregorian music is.