Most tomes will be potentially important in at least one quest somewhere in DStorm.
The tomes added, though, are the first parts of a couple larger volumes (which is why there is a '1' beside them). In order to gain a complete bit of information you will need to know what is in every part of the volume. The next part of "Frionia's Curse", for example, will have the title "Frionia's Curse (2)".
Seemingly unrelated tomes could potentially have some important link, and it is advised to compare what they say once you obtain more than one.
Also, while every tome will have some sort of importance, they may not all be 100% accurate. If a tome is not accurate I did it on purpose, and comparisons with other sources and tomes would be necessary to determine the truth.
Upon buying and using a tome it will be PMed to you. There could be an error relating to an invalid link, but it doesn't mean anything (just click on your inbox).
Also, how you handle the tome is up to you. This is where the story becomes significant and a character's actions could be reflected in the actual game (Age of Arcana) when it is released. You could keep the information to yourself and try to secure your own relative superiority in knowledge (and keep hidden quests away from others), try to create your own library accessible by others, or whatever else. You can even twist the tomes and give your enemies false information to throw them off.

So that's basically it for tomes... Expect others to appear in the future as well.