Is it incumbent upon the student to inquire of the professor who prepared a summary of a copyrighted book whether he has obtained permission from the author, especially if not seeking permission will result in difficulties in studying or sin in benefiting from the summary and lectures?

There is no harm in benefiting from a book summary, and there is no need to seek the author's permission; this is an excessive scrupulosity. The general principle in a Muslim's dealings is that what is in his hand belongs to him. Most contemporary jurists have held that summarizing books does not require permission from the original author, because it is the researcher's own effort, and it is recommended to mention the source. Scholars have always abridged books to make knowledge more accessible. Sheikh Bakr Abu Zayd views quoting as a legitimate benefit about which there is no disagreement.