For nine of the Arts, there is a basic text that, over time, has come to be accepted as the preferred primer for a magus seeking the competence necessary to train an apprentice. These texts, called the Roots of the Arts, are widely and cheaply available. A Redcap can arrange the delivery of any of these texts, for a very small consideration.
... but then never mentions which nine, nor the qualities of these books. Do any Ars Magica books have a list of these "standard" books?