1) Writing summa
I do not really understand this, or maybe I do. Say that my master has 40 in Ignem and a Communication of 4, no virtues that aid him in any way.
This means that he will be able to write a book at level 20, with a quality of 10, from what I understand.
He can choose to write a book at level 15, and add 5 to his quality for a total of 15 or he can write a book at level 10 with 20 in quality.
2) Reading a summa
So if I write this Ignem book from the example above I will (as I have no virtues that help me) get Level + Quality number of XP to put into Ignem.
If I read the level 20 book, I will get 20 (Level) + 10 (Quality) = 30 xp per season I read it
If I read the level 15 book, I will get 15 (Level) + 15 (Quality) = 30 xp per season I read it
If I read the level 10 book, I will get 10 (Level) + 20 (Quality) = 30 xp per season I read it
3) Last Question
If I understand this correctly, the only thing that changes is the time it will take to write it, as a student
So if my master has written these three books, it does not matter which book I read? The only thing that matters is that it took a longer time to read the level 20 book than the other two books. All books give me as a student the same amount of XP
The level of a summae is the point at which it stops being useful to a magus. The quality is how much XP it gives per season.
Using your examples, let's say you have a score of 1 in Ignem
If I read the level 20 book, 10 xp per season I read it. I can read it for 21 seasons before I reach the level limit.
If I read the level 15 book, 15 xp per season I read it. I can read it for 8 seasons before I hit the level limit.
If I read the level 10 book, 20 xp per season I read it. I can read it for 3 seasons (rounding up from 2.75 seasons) before I hit the level limit.
Summae can be read for multiple seasons, tractartus can only be read once, for 1 season.
And, having read your 'new SG' thread, if you are playing 4th edition the rules are not the same as in 5th edition.
Please specify which ruleset you are using, it makes answering questions much easier.
Eg in 4th ed, you can gain a maximum of 3 in an Art or Ability per season - 5th ed has no such limit - that isn't 3 xp, it is a gain in the value of the Art or ability of 3. However, you also gain your 'concentration score' in xp when reading (also a 4th ed rule). This makes reading books much better than alternative xp sources, and means that the very best ability to put all your starting xp into is concentration - unless the SG limits it. And you get 1 xp in concentration per season spent studying from books...
My advice to any starting SG would be to limit both the quality and the quantities of books available. It is easy to add books as rewards for adventures; it is very hard to remove ones you already gave out. Burning the covenant library can only be done so many times... I would allow each player to pick one decent book eg L10 Q15 for an Art or L5 Q15 for an ability and otherwise allow them to start with a handful of tractatii.
It's a function of referring to the Advancement Table in the main Ars Magica 5th Edition text. Summa can be read multiple times until they reach their level limit, and they provide experience points equal to the quality level each time they are read. The level of the summa determines when the book stops providing experience points.
Start wth the lowesl level/highest quality and read until the book doesn't provide any benefit. For someone with a score of 0 using the three summae you listed, it would be 2 seasons with the L10Q20 book, 5 seasons from the L15Q15 book and 11 seasons from the L20Q10 book, the last season you'll only get 5 experience points.
I also agree with Gilarius with regard to books and adding them to the player covenant...
Oh I am sorry. My wonderful girlfriend was at a Roleplaying Convention which I unfortunately could not attend due to my studies, and she bought me the 5th Edition rules as she thought it was something I needed. So I will go by those rules instead. So my questions is about the 5th edition.
Fair enough, Viva Tremere. 5th ed is much better, however read the 'fluff' from 4th ed too; it is very good for getting the 'feel' of mythic europe.
Regardless of edition, keeping your players hungry for better books is quite important. I'd also, for a new SG, recommend ignoring all the ways in 'Covenants' of improving the quality of written works. You can add them in later on if you want to and it is just confusing for new players, plus book learning is already one of the best ways of learning and it doesn't need to be made even better, outclassing eg practice or learning from Vis, by even more points.
Who writes summae? Few PCs until they can write awesome ones (in my experience), but many magi write tractatii. The 5th ed rulebook and 'Covenants' make it very easy to buy summae with the point system, and they are very useful to players. As a SG, giving out tractatii is much better.
The best game I played in was for new players. Only one of us had played before, and the SG. We started in a totally unknown location (having been teleported to the wrong place by a senior magus immediately after being presented after gauntletting) with no resources, equipment, or library. It allowed us to explore the game system where our challenges were simply to obtain food/shelter/etc. And then to find caches of useful gear from the senior mage's covenant as we grew familiar with the rules (the initial botched teleport was the excuse for them being present). And then to meet potential allies/enemies as we explored further on.
Eventually we made contact with our fellow mages and then could start learning about the rules for Tribunals and the Code.