The notes are not Galileo's, nor does it contain even his autograph. The notes were written, so far as we know, not by some other famous person but by unidentified contemporaries of no guaranteed authority. Nevertheless, they are valued as a contemporary response, and may be valued all the more, nowadays, for being the work of nameless readers. The same criteria could be applied to the book on the bus, but its annotations have negative value. About the time that the British Library displayed its Galileo, I picked through a batch of books rejected from a college book sale.
All markings are in ballpoint ink.
The reader, a student, appears to be conscientious enough to look up unfamiliar terms. Should have some rules or could screw it all up. So the response continues, the comments being generally brief and, to be honest, banal. We have no way of knowing whether the notes in the Galileo are any more sophisticated than these. It is quite likely that they, too, are student's notes, and if we were in a position to compare them, we might be able to say something about changes in educational methods and results over time.