Scrying creates a sensor. It says:
the spell creates an invisible sensor within 10 feet of the target. You can see and hear through the sensor as if you were there. The sensor moves with the target, remaining within 10 feet of it for the duration.
What level of control do you have over that sensor? Can you move it to any point within 10 feet of the target, for example to be able to read in a book they are reading, or to maximize the area around the target that you can look at? If not, where would the sensor appear, and how would it follow the target?
Best Answer
You don't seem to have much control
You cite the important part, and along with
the spell only seems to guarantee that:
So no guarantee of reading their book, it's up to chance (i.e. the DM).
But you can make it work
So you've scryed the target and see a book in front of him. Well, that means you have seen their surroundings, the location. Now you can cast Scrying again in the location mode:
And it shouldn't be a problem to specify a position for the sensor so that you have a clear view of the text.