For publications where downloading is restricted, community-developed tools can automate the process by fetching page images and merging them into a PDF. anyflip-dl (Graphical Tool): A user-friendly desktop application available on GitHub (AlimulK)
If the author has disabled direct downloads, you may still be able to save the content using your browser's print function: convert anyflip to pdf free exclusive
For flipbooks that are restricted from downloading, community-developed tools can automate the conversion process: For publications where downloading is restricted