It would still get some warping, IMO, as you're casting multiple spells on the text, so it is subject to multiple "continuous" effects. It might be even less warping, but in this case, I would track fractional warping rigorously.
I think you're overestimating the benefit of this sort of item. We're talking about an effect that's going to come in somewhere around level 50, which should be hard to create in a game with normal power levels and which costs serious vis. Added to that, you're putting an arcane connection to your library in a movable item, which ought to be of serious concern to the Covenant. All in all it doesn't seem like a great idea to me when compared against hiring an extra scribe and imposing some sort of reasonable system of rotation for sharing books in the library.
Applying warping rules in such a fashion would, I think, lead to a very dark Mythic Europe where everything touched by magic eventually degenerates and becomes corrupt. I don't want a World of Darkness feel, so I'm much more conservative about applying warping. To come back to the example at hand, if a magus creates a crystal ball that continuously looks at a far away city, would you start warping the entire city?
Not really. The idea that you use Peering Into the Mortal Mind willy-nilly makes it dark for me. Use it on your grogs all the time, yeah, they're going to develop some intersting flaws. Use it on a couple of peasants or townsfolk to get important information, you inflict a warping point. Do it to the same person 5 times in a row, they get a minor flaw related to the underlying effect. I don't see this being quite as big of a problem as you do. It's one of the reasons why I hem and haw with warping on BoAF and IoL, despite how strongly stated I am. I still think about warping for those spells all the time. The only defense I have for not putting warping on a recipient of the aforementioned spells, is that most characters who get hit with these spells are likely dead, unless they are a little bit lucky with their soak rolls. On average (assuming die rolls of 5 for damage and soak) those spells will kill anyone of Size +2 or less with average stamina.
Because it is as you say, a logistical problem, but one I'd expect any half-way-sensible troupe to be able to resolve in under 2 mins.
And if ERiaBP bothers you, you'd be horrified at some of the other solutions I've seen.
To paraphrase someone who said something in another forum, there are seldom good magical solutions to behavioral/logistical problems. Like I said, I'm not horrified by them. I just think that if you're going to choose the path of ERiaBP, need to consider warping, and the other effects within the Order. I see people (I'm not saying you're one of them) complaining about the power creep of Ars Magica, and then on the other hand resist some very reasonable rules interpretations that tamp down on things pretty well...
This.
Exactly.
- "I don't understand, it's obvious that there should be huge volume of high-quality books studied massively by every apprentice and magus for at least 100 years per magus"
- "Hum, maybe this isn't so because of this and that"
- "Oh, no, no way, this is nonsense"
Note that, for Peering into the Mortal Mind, the Target is Mentem (the mind of the target) and the target is that person's mind, so warping occurs, even by a very strict reading of the rules.
Also, books being warped by magic used on them is, IMO, quite flavorful, this allows books with quirks and personality. What's not to love?
I have complained about power creep, but my problem does not stem from the sharing of books, it is rather more fundamental.
Arts based on XPs changed the game, significantly.
I wanted to go back to this, because something about it bothered me, but I couldn't put my finger on it, and then it came to me. This is a player logistics problem, but when viewed through the lens of the character, it might not be known. My character doesn't want your character to know what he's studying. Player to player, I have no objection. But my character is secretive, and distrusts the other magi of the covenant (remember when magi, even in covenant, were somewhat confrontational and opposed each other, do you have sagas like that now). So, when my character wants to read a book, he goes to the library and gets it, and leaves any one else who had plans to read the book picking a second best choice. Or, he finds it's gone and has to make the second best choice, himself. So unless the characters plan, and make copies of all their books...
You said the troupe, which means to me that this is really a players discussion. Players will often time optimize the scheduling of available resources, but I don't think characters can do so quite effectively, as noted above. Having the logistical problem solved means the characters knowing of each others study plans, and also arranging resources to ensure that another copy of the desired book is ready. But even then, there's the catch. If resonant materials were used in the first book, it will be, unless some adventure is undertaken to acquire proper resonant materials, a book of slightly lesser quality. So again, the logistics don't play out perfectly, and character motivations should color any discussion about optimized scheduling.
I may have a pretty bad memory, but I'm pretty sure Arts were based on XPs since 3rd Edition, when I started. Maybe you've been with the system since 1st Edition, I don't know. This is another version of the good old days argument, and I really don't buy it. If the old way were so much better, it probably wouldn't have been changed...
For me, Arts based on XPs would be alright if the XPs were not so freely available. Covenants suggests that it's easy to obtain a Q11 Tractatus and to further add an additional XP for engaging in letter writing. Not only does that create much faster advancement that the older system but it completely overshadows any other learning method.
The problem, though, is the existence of these massive libraries, not some remote viewing device. As I've pointed out earlier, it's much more reasonable for a Covenant to hire a scribe or two than to spend 10 vis and some high level Magus time creating an object which, if lost or stolen, provides outsiders with an arcane connection to their library.
As to the warping issue...de gustibus... I don't want magic to feel like radioactivity. This isn't Call of Cthulhu.
Just to make a point the mage had a link to its own private library. And i dont belive that is easier to LoH than to use a device.
I don't think these massive libraries exist, though. It's a function of the storyguide and the troupe, and it's really easy to set this guideline. IF you're talking about vis, and making an item, in reference to ERoaBP, it's not at all magical. And yes, arcane connections can be lost and stolen. Happens all the time, and is the basis for many a story, so I find that objection to be flawed at best, spurious at worst.
Well, it is RAW, and as I said, I have some problems with warping, too. But again, it can be mitigated. And warping, IMO is how these magical auras come to exist.
Perhaps but the guidelines in Covenants strongly suggest that books of such quality are easily and readily available. We're talking about what's suggested as normal by the published books, not what any particular troupe might choose for its own game.
I was referencing the proposed magic item, not a stand alone spell, and specifically the general use item that I believe comes in around level 50. This requires a lot of vis. If we're talking about the ERoaBP spell from Covenants, its level 35 and links to a particular book which the caster has an AC to. A general "link to library" version would be higher level. If Magi can cast such high level spells in their early or mid careers, power levels have already escalated so much there's not much left to worry about.
If the magical "book" is stolen, not only do outsiders have access to the entire Covenant library, but they can easily cast spells from anywhere in the world which affect anything inside, with enough of a penetration bonus that Aegis of the Hearth probably won't be much of a protection. Presumably the AC will be "fixed" and therefore permanent. I'd think twice before making such an item.
Besides, it's not so hard to scribe extra copies of books. If the book exists and the owner is willing to allow a copy, the mundane considerations are not large. Books were not so uncommon by the end of the Medieval period and this is the organizational level suggested by the recent Tribunal books, not the organizational level of the early Middle Ages when decently sized book collections really could fit into single chests.
I remember this sort of things. Toobad people I play with have bandoned them, without actually learning to work together, for a common goal 
As for the rest of your statement:
Nonono... when you take the book, others can see which book is missing!
You'll need to be sneakier than that!
3rd edition did not have XP based Arts, but a lot of troupes were using it as a house rule.
Why? Becasue it was better? So it was thought. To me, it was merely more aestethic.
The power curve was different.
True... but if I sneak into the library on day 4 of the season, take the book and return it on day 85, might it be possible no one notices? And, then, there's the issue of do they know who's taken it? My magus might tell the librarian to say nothing about who has the book, except that it is a magus of the covenant. Plenty of other targets...
I guess my memory of 3rd Edition is incomplete, can you refresh it on how Arts were advanced?
Edit:fixed quotes
It's not partcularly relevant for the discussion at hand (of the Fire Imp Notebook), but sure.
Full level advancement only.
If your source had a value above your Art score, your Art score increased by 1
If your source had a value above your Art2 score, your Art score increased by 2 instead
If your source had a value above your Art3 score, your Art score increased by 3 instead. This was max.
If your source had a value not above your Art score, your Art score increased by 0
There was no tractatus.
Since studying from Vis involved rolling a stress die (value equal to (N*die roll)+aura, N being the number of pawns of Vis used, capped at 3), it was highly variable and there were lot of wasted seasons (in my experience).
With Arts base on XPs, you never waste a season as such. You will always accumulate something if you study a given Art.
And pretty soon, that piles up - especially with the hgh quality sources that are the default assumption of the line.