Is it permissible for a learner to benefit from information whose source is not mentioned, and is his reading of a book from which it was quoted considered an infringement on the rights of the original authors? And does the reservation of all rights prevent summarizing the book or quoting from it?

Copyright for the author and publisher is reserved, and infringing upon it is prohibited. It is permissible to benefit from the information in the book by applying it, summarizing it, or conveying it to students and the like. Quoting from any book is permissible Islamically, provided that every statement is attributed to its owner and conveyed faithfully and without deceit. Whoever does not adhere to this is in violation of the trust of transmission, like one who is satiated with what he has not been given, and is censured as one who wears two garments of falsehood. As for the reader and one who peruses works that do not attribute information to their owners, its permissibility is self-evident and raises no doubt.