I know some really good books which are extremely long (e.g. 1000++ pages). It would be good if more people can know the content of those books. Unfortunately, they did not even start to read them unless they were much shorter, which is reasonable, not everybody have the time and/or discipline to finish such a long books.
What were the legal bounds or ethical issues if I created a shortened/summary version of those books (let's assume I do not copy any sentences from the original books, but I may use some of the examples of theirs and the logical structure of the books would be the same) and I self published them on Amazon.
I would recommend to my readers to read the longer/original version of the books if they liked mine or if they need more detailed information.
I feel that there is a lots of work to reduce the content of those books (again, I do not intended to just delete some paragraphs but I would write new books) and the best would be that if I do not have to deal with the original publishers.