Of course it is. You can use anything in the public domain without asking permission or paying for rights. But there is a distinction between copyright infringement and plagiarism; they are not identical. Taking material from any source, and allowing the appearance that it is your original work, is plagiarism. You might not go to jail for it depending on its extent, but you would surely end any hope of a distinguished academic career.
Works for which the term of protection has expired are in the public domain.
A taking by Eminent Domain.
The broad assumption is that if something is in the public domain, there is no incentive for anyone to care for it. This is referred to as the tragedy of the commons, but has been fairly consistently disproved. For example, films in the public domain are much better cared for than films that archivists are prevented from migrating to new media by copyright restrictions.
the copyright on amos and andy expired years ago and it is now public domain. no one can purchase the rights to something that is now public domain.
One can find pictures of puppies that are considered to be in the public domain on public domain picture collection websites. These are a few of those: Wikimedia, PublicPhoto, Pixabay, PD photo, Photos Public Domain, Picdrome, Alegri Photos, Free Photo Gallery, Public-Domain-Photos, 4Free Photos, Free Stock Image Site, Public Domain Files,Public Domain Depot, Open Galleries, Free Images Collection, Free Digital Photos, Public Domain Photo, Project Public Domain Pictures.
Union for the Public Domain was created in 1996.
Yes, Shenandoah is public domain.
Center for the Public Domain was created in 1999.
Public Domain pictures are images, photographs, or pieces of art that are free from copyright regulation; this makes them public domain. Companies such as Public Domain Image and Public Domain Pictures offer access to images for free. Other great companies are USA government website, as many of their images are public domain, and PD Images.
Yes - all questions and answers on this site are in the public domain. Even your profile is in the public domain (though only you can edit it !)
All of Shakespeare's plays are in the public domain. Pygmalion is in the public domain. I'm sure there are many, many more too!
Written laws, as works of the government, are in the public domain.