There is a different book on a pedestal later in Maxos temple that adds the 'dragon no more' quest. First you need to get into the start of the temple, if you haven't already, and pass 3 tests.
The book in the entrance mentions something broken being made whole, which is a clue about what to do next (or you could just explore everywhere).
There are 4 vases on pedestals around the room, one of which can be selected and operated like a lever to open the second door.
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