How to download a PDF book to your device

Most devices already have PDF readers installed, but if yours doesn't, adobe has a widely used:

Free PDF Reader

If you already have a PDF reader on your device, make sure you are using the latest version of the software! 

If you'd like to read one or both of your PDF monarch butterfly books on your computer or another device, see directions to download and view to your specific device here:

How to download and save a PDF file to iBooks

How to transfer and read PDF files on Kindle Fire

Best PDF Tools for Chromebook?