The Sirian's book was supposed to be written by Micromegas, an inhabitant of a distant planet who was visiting the Earth with a creature he had met in Saturn. He promised the humans of Earth that he would hand them a miniature volume for their convenience, that would contain the nature of everything, so that nobody would have to debate about the ideas of different philosophers anymore.
However, when the book was opened in the Academy of Science in Paris, the secretary noticed the pages were blank.
This can be interpreted in different ways, as Micromegas was able to make different comparisons in his journey. First, with his Saturnian companion, and then with the small humans of Earth. He had a lot of knowledge, but was also open to learn new things. In the end, he understood that there was more to proportion than size and distance.
After circumnavigating the planet in 36 hours, and listening to the people in the ship, he learned about humanity's ignorance, wars and injustice. He noticed they liked to quote different philosophers, without necessarily understanding what they meant. Most likely, he decided to leave Earthlings to evolve at their own pace, with their own singularities rather than showing them a wisdom of ages that was not theirs.
The blank pages may mean that he wanted humanity to write their own philosophy instead of exposing them to the knowledge of a different planet which was completely different in size, age and wisdom. Having seen human nature with his magnifying glass, the gift of knowledge could be used for evil purposes rather than to their benefit. Last of all, life is complex and no book could be written about humans, except than by humans themselves.
