Is it legal and legitimate to download free PDF ebooks? A friend recently stumbled upon a treasure trove that would be enormously helpful to my UXR students but I am unclear if I should share it.

The site seems safe (as in no buggy stuff going on). It has tons of books I previously purchased for my personal UX research library in PDF versions for download.

The terms say:
XXX lets you download files from the public web using its servers – the servers act as a proxy for you. This means that no data is controlled by us and you must have the legal right to download the content you are accessing through our servers; this site should not be used for any other purpose.

The site does not include a link to where the content originated from. I'm curious to hear your thoughts.

Attorneys? Authors? Everyone is welcome.

image by PrintsByArtist on Etsy