Any comments in brackets '[]' belong to Tetris no Miko, who translated these questions for me and you.
Did the book, perhaps, choose its own Mikos?
The way in which those from the book world who come
into the real world age
Did the book call out to Miaka?
Why did the book let Miaka in the second time?
What was the book doing at the library in the first place?
What if a person who was not chosen to be a miko opened the book?
Just how big was the world inside the book?
The book was not translated in the anime, so why...?
Did the book, perhaps, choose its own Mikos?
If any other female (naturally, a virgin) besides Miaka or Yui had opened the Shi Jin Ten Chi Sho, would she have become Suzaku or Seiryuu no Miko instead? I'm sure many people think that any other female would have been chosen, since Miaka and Yui were the first virgins to open the book after Suzuno had returned to the real world. But is this really so?
If that is so, then is the only requirement for a Miko that she be a virgin?
Or is it perhaps that the main proviso is that she be a virgin, but other than that, the gods bring in only whom they feel to be worthy of Miko-hood?
This means that Suzuno, Takiko, Miaka, and Yui were not just virgins who happened to open the book, but perhaps they were actually chosen by the book its self.
Or maybe not. Maybe no matter how cruel, devious, annoying, or ugly (even worse than Taiitsu-kun) you were, as long as you are a virgin you can be a Miko?
The way in which those from the book world who come into the real world age
Currently being translated...
Did the book call out to Miaka?
Was Miaka's discovery of the book mere coincidence, or was it fate?
Of course, only the book its self can answer this question for sure, but I believe that the book did indeed call on Miaka.
Was Miaka's dropping of her pencil and noticing the door to the important documents reference room was ajar, and the book dropping off the shelf when Miaka and Yui came into the room mere coincidence?
Of course it's not coincidence! Anyone can see it is very likely that the book called on Miaka.
To take it a step further, I say it was fate that brought Miaka to the library that day in the first place. Another possibility is that whenever Miaka had visited the library, the book had sensed the presence of a possible Miko and had made its self visible for Miaka to find it one day.
Going back to the Taka theory, perhaps the book realized that one of its characters, Tamahome, had been reborn 18 years earlier as "Taka" and understood that it needed to bring Miaka back into its world to complete the cycle.
Though I guess this is a question each of us as a reader has to figure out for ourselves...
Why did the book let Miaka in the second time?
[*Remember that in the manga, both Miaka and Yui left the book-world together the first time, then Miaka went back alone the next day into the book]
It may have been fate that first brought Yui and Miaka into the book, but it must have been fate when Miaka argued with her mother the next day and by her own will, entered the book again.
Perhaps it was the book's doing that caused Miaka's mother to find her diary and anger Miaka and cause her to enter the book.
Maybe upon Miaka's first arrival into the book, the book chose her to be Suzaku no Miko and was upset when she left, so it arranged for her to come back.
But what if it had taken Miaka days, even weeks to reenter the book? Unfortunately, the story and "life" in the book-world might have come to a dead stop until she entered it again.
What was the book doing at the library in the first place?
Had the book been strategically placed in the library in Miaka's and Yui's neighborhood?
After Suzuno had come back into the real world, what did she and her father do with the book?
It is very conceivable that Suzuno had a fond place in her heart for the book due to her experiences with Tatara and her Seishi.
Luckily for Suzuno, she made it out safely and went on to live the rest of her life in the real-world, but knowing of Takiko's tragedy, Suzuno and her father must have wanted to keep the book in a place where no girl (virgin) could find it.
So why did it end up at the library?
When it was discovered that the book was fire-proof, I'm sure Suzuno's father had it sealed in a safe place, but what with WWII and the aftermath, the whereabouts of the book might have gotten lost...
[*Ooh! And it was discovered by an American soldier! Fics, anyone? ^_^; -TnM]
Then it was perhaps discovered later and then brought to the library in Miaka's and Yui's neighborhood? That is a possibility...
What if a person who was not chosen to be a miko opened the book?
Just how big was the world inside the book?
The book was not translated in the anime, so why...?
Watase Yuu answered this question herself in the original manga. Tasuki no Miko (the original) has translated the answer on her website, here. It is question #4.