A word of caution: You should always identify the source and copyright status of a given work, especially if you suspect it is in the public domain. (rocketlawyer.com)
So, Google captured large numbers of out - of - copyright public domain books, in - copyright books where publishers explicitly gave permission, and a whole gray area of books of indeterminate copyright status. (davidderrico.com)
Project Gutenberg carefully verifies the American copyright status of each of its eBooks, so you may freely download all texts from this source. (victoria.tc.ca)