Q. If I can't put a hold on a book because it's checked out by a professor, but it's important for my dissertation, can I request another copy

Hi can you tell us the title of the dissertation? Holds are a little confusing. If you can't put a hold on it, that probably means it's not checked out. A hold means that you're "next in line" to get the book if it is already checked out. I can double check for you though.