After looking with some care at the game mechanics it seems to be that there are significant limitations on the types of book that could exist, because it is otherwise hard to see how the books come to be written. These limitations drop reasonably directly out of the defined game mechanics:-
In out-line the Ars Magica 4th Edition rules are as follows:-
In fact there is a lot in common between the three types of text book. All are written at a given Quality and when studied this produces a Study Total for advancement. For Arts, the Study Total translates directly to experience points. For Knowledges, the Study Total is divided by 5 (rounding up)[2]. (There is also a 3 levels per season advancement limit.) Excepting a few limits and modifiers, the basic formulae are the same for all types of book.
Quality = Communication + Scribe + <constant> (Author's Stat.s)
Study Total = Intelligence + Concentration + Quality. (Student's Stat.s)
The first point to note is that the Quality depends only on the author's stat.s and not on any decision made at the time of writing. There are practical limits on the range of the (Comm. + Scribe.) value. Values below 1 (Scribe 3, Comm. -2) or above 10 (Scribe 8[3], Comm +2) are likely to rare. Note that the existence of virtues like Strong Writer and the possibility of a highly experienced author make Comm+Scribe scores of 16 possible. Similarly a Incomprehensible[4] Ex Misc magus could have a score of -5, however it is unlikely he would do any writing. The limits are accordingly not rigid but the vast majority of books should be written within this range. Most books should be near the middle of this range. [If you allow age and poor maintenance to reduce Quality, this effectively removes the Quality minimum.]
The values for the Quality constants and resulting normal ranges are:-
| Type | Quality Constant | High Quality | Low Quality |
| Summae | +3 | 13 | 4 |
| Libri Questionum | +6 | 16 | 7 |
| Tractatus | +0 | 10 | 1 |
Both Libri Quæstionum and Tractatus are written in a single season, and can be used by the student for only a single season. Summae may take several seasons to write (depending on Target level) but can be used by the student continuous until the book's Target level is reached.
Target-level of a Liber Quæstionum is the level of student that the book is intended for. The student suffers a 5 point Study Total penalty for each level of mismatch between their current level and books level. (This causes a slight anomaly at low levels[5].)
Each type of book has an additional authoring limitation:-
In designing a Covenant library, books are costed in points according to
formulae.
| Book Type | Hermetic Book Cost | Mundane Book Cost |
|---|---|---|
| Summa | 2 x (Target + Quality) | 2 x (3 x Target + Quality) |
| Liber Quæstionum | Target + Quality | 3 x Target + Quality |
| Tractatus | 3 x Quality | 3 x Quality |
The Covenant generation rules define the "average[7] Covenant" to have 450 points of Hermetic books and 300 points of Mundane books. This translates to:-
The "average" covenant's Hermetic library consists one of:-
The "average" convenant's Mundane library consists one of:-
It is naive to believe that books will be written to be useful, rather for the aggrandisment of the author. Nevertheless the books which are widely copied and hence widely available will be the useful ones. It is also fair to assume that students will study the books available in the most efficacious order. Accordingly it worth considering what books are most useful.
Due to their providing the best Quality score for a given author, a large number of Liber Quæstionum of appropriately spaced levels, is ideal for the student. However note that the student's current level must precisely match the book's target level. If there is a mismatch of even one level, then the student is better off with a Summa by the same author. Such series would have to be written anticipating the students progress, hence of a particular aptitude of student. Such a series is likely to be very expensive.
e.g. Consider a Libri Quæstionum series to teach Magic Theory to level 6. Assuming a reasonable Quality of 10 most students can expect 3 xp. per season. So seven seasons and seven books are necessary to complete the course. The books are of levels 0,2,3,3,4,5 &5. This total 70 Quality levels and 22 Target levels or a point cost of 136 (= 70 + 3 x 22)). They would take the author 7 seasons to write. A Summa by the same author of level 6 and Quality 7 would cost only 50 points, and 2 seasons to write. However it would require a more adept student to maintain 3xp. per season. A student with (Conc. + Int.) under 4 would take 11 seasons instead of 7.
Whereas series of this type may exist for very popular subjects, they are likely to be rare. Where they do exists they are likely to be at reasonable low levels, where the number of books required for the course is not excessive. As Arts are learnt much faster than Knowledges and the books are cheaper, Art series will can reasonably go to much higher levels than Knowledge series.
These provide next fastest progression and at far lower cost. It is more likely that an exceptional master of a given skill will spend a few seasons writing a Summa than spending several times as many writing a series of Liber Quæstionum.
These will be the definitive text books. There are likely to be a number of these, varying for comparitive beginner books to a few books written by the greatest master of the relevant skill to date. Examples of the later are likely to viewed as especially valuable, and might be available for use (hire) but not for copying.
These are poor man's Summae. A Liber Quæstionum with a target level of zero will normally take a student to level 3 in an Art or level 2 of a Knowledge in a season. Accordingly these are as useful for beginners as, but cheaper than, a low level Summa which would also be exhausted in one season. The Liber Quæstionum is about half the point cost of the equivalent Summa and higher Quality. However note that as the Summa is no harder to write than the Liber Quæstionum and typically are a little easier to copy, Summa at this level will also exist.
These will largely be with a target level of zero. Although some may have a second book, which takes off where students have got to after the first. However beyond that it definitely counts a Liber Quæstionum series.
Tractatus are the lowest Quality, but have the advantage of no target level limits. Accordingly advanced students who are beyond the level of the best Summae and Libri Quæstionum can only use Tractatus. They will also encourage (demand) everyone who can write Tractatus for them do so whenever possible. Hence for popular subjects there should be very large numbers of Tractatus in existence. However the Quality will be very variable.
The conclusion is that most Libri Quæstionum will (especially for Knowledges) be largely low level (beginners books). The books for more advanced students will be largely Summae, with Tractatus for experts. The point at which a student has to stop Summae learning, thereby loosing quality and needing a new book per season will be put off as long as possible. Accordingly there will be get value (and kudos) in writing the best (highest target level) Summa.
Note that there is no guarantee that the greatest expert has a good authoring score. Accordingly the highest level Summa may often be of lowish quality. There may also be lower Target but higher Quality Summa by less skilled but more literate authors.
The very best Summae will have been written by monomaniacs who spend their entire lifes studying one subject and then write the definitive works in later life. There is no guarantee that such monomaniacs will fix on anything sensible so in principle there could be very good works in some unlikely subjects. However it is far more likely in a few obvious subjects. (e.g. There will be good Ignem Summae from House Flambeau, and good Magic Theory Summae from House Bonisagus.)
If there has been such a monomaniac then the best Summa may approach half the maximum level of each skill achievable in a life-time. To some extent what is achievable depends on the number of Tractatus available.
The levels depend type of skill and a number of other assumptions, like the availability of various learning aids and the dedication of the author. The follow are my estimates, but under different interpretations of the rules or different assumptions, the values could be different. There is a separate discussion of this.:-
Obviously the precise interpretation of rules is up to the individual Story Guides. However this is what I would do.
These are intended as guidelines rather than strict rules. Getting close to them should require some story to justify it. Breaking them should require a good story.
Ian Miller
[1]Note Knowledges only, not Talents or Skills which cannot be learnt from books.
[2] This means it is very easy to achieve 2 x.p.. per season progression, and practical to achieve 3 x.p. 4 x.p. can only rarely be achieved.
[3]It takes about 50 seasons of practice to get to level 8, a further 30 to get to 9, a further 50 to get to 10 and a further 150 to get to 11. This makes 10 the ceiling for most purposes.
[4] The flaw Incomprehensible applies only to magic writing and hence only to spells and Hermetic books. Mundane books cannot suffer this penalty.
[5]E.g. Consider a Liber Quaesitonum of Quality 8 and Target level 3 being studied by two students each with Int. + Conc. of 4. One student has 9 x.p... (level 3) and therefore matches the book perfectly and gets a study total of 12 and advances to 21 x.p../level 6. The other however has 15 x.p. (level 5), so suffers a -10 penalty and accordingly gets only 2 x.p.. and fails to reach level 6. Whereas studying the same text the less advanced student should clearly catch up somewhat. However leap-frogging the more advanced student seems unreasonable.
[6]The level limit for Libri Quaestionum is problematic at the lower levels. Even a low quality L.Q. of target 1 in an Art could take the pupil from level 1 to level 4 (9 x.p.s) is a single season, but on the rules could be written by someone of level 3! ?A target level zero book could be written by someone with no skill??
[7]"Average" in this context is an arbituary datum for designing covenants, rather than an average of actual covenants. I understand that experience in actual play generates rather larger libraries than this.
