Tractatus
In ArM4 or ArM5, a tractatus is a book that teaches in depth about a limited sub-topic within a particular Ability or magical Art. The word tractatus is both singular and plural.
Covenants (Fifth Edition) has advanced rules for writing and improving tractatus.
Studying Tractatus
A character who studies the tractatus for a season gains experience points in the Ability or Art about which the tractatus is written. The amount of experience points depends on the Quality of the tractatus; see ArM5, page 165.
- Unlike a summa, a character can only benefit from a given tractatus once.
- Unlike other books, a tractatus gives the same benefit regardless of the character's score in the relevant Ability or Art. Beginners and experts both get the same number of experience points from studying a tractatus.
Writing Tractatus
The prerequistes for a magus or other character to write a tractatus are given on page 165 of ArM5. They include minimum scores in the Speak Language Ability, as well as in the Art of Ability that the tractatus is about.
References
- Books, ArM5 page 165 (covers studying tractatus)
- Writing Books, ArM5 page 165
- Extended Suggestions for the Quality of Books, Covenants (Fifth Edition) pages 87-89