Find the book on WorldCat.org. Note the nearest library that owns it. Request via your local ILL. If you need it tonight, check the Internet Archive’s "Controlled Digital Lending" section.
Similar to Unpaywall, the Open Access Button is a website and extension. If it cannot find a free copy, it will request the author to upload one. Many authors are happy to share their papers legally via email. au1lib.org alternative
This article provides two things: First, a list of for accessing academic content. Second, a critical guide on why shifting from shadow libraries to legal alternatives is better for your research, safety, and conscience. Find the book on WorldCat
Moving from a known site like AU1lib to random alternatives requires caution. au1lib.org alternative
