Are you legally allowed to draw ideas from a book without permission?

Question

My plan is to make a YouTube channel with a curriculum based on a pretty well-known textbook.

I want to reformulate and re-present the ideas in my own way. I will not take any direct quotes from the book. I will try to make money off of the videos.

The way the theory of the videos lines up completely with the theory of the book, it is unquestionably derivative of that book. I remember hearing about lawsuits where a musician sued another, even because they thought a chord progression, and maybe melody, sounded too similar to their own.

Is the nature of copyright that you own the ideas in your book, not just the words?

For example, I am pretty sure you cannot sell a book with characters resembling those of Harry Potter, even if fan fiction, a new story. Perhaps that’s trademark infringement?

Assuming I make it publicly known where I drew the information from, can the publisher claim infringement/intellectual property theft for reselling a theory?

In the modern world, what is the precise limit of what part of a book you can no longer own?

Answer 1

While the answer of gnasher729 has most of the main ideas, note that one of the things that copyright law generally protects is the ability to make "derived works". These rights are reserved to the copyright holder. (Caveat: copyright law varies.)

So, while the ideas are free to use and you can't use the specific expression, you also need to avoid making a derived work without permission. The way you describe your work is probably not allowed, though it is up to the copyright holder to complain.

One important consideration in copyright law is whether some use reduces the economic value of the original. If your videos make the book unnecessary then it is almost certainly infringing.

But the solution is to ask the copyright holder for permission, fairly describing your work to them. It isn't outside the realm of possibility that they will consider it an enhancement of the value of the book (or neutral) and give you explicit permission. They might even advertise your work for you.

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Note that "ideas" per se are not copyrightable, nor owned by anyone. IP law is concerned with creative expression of ideas (or "devices" in the case of patents), not the ideas themselves.

Also note that copyright is intended to eventually expire, though that has been called into doubt recently. But old things can be reused/repurposed. You still need to avoid plagiarism by citing originals, however.

Finally (I hope), if you couldn't draw ideas from the works of others, science and scholarship in generally would halt. We build on the ideas of others.

Answer 2

Ideas are not protected by copyright whatsoever, it is the expression in fixed form (usually written, sometimes audio or video recording) that is protected. So you can take ideas.

Be very careful not to copy anything from the actual book. That is difficult for some people and may require a lot of discipline. It is hard (for some people) to read something in a book and then to express it in your words without using anything from the book.

Your "Harry Potter" example is based on trademarks. You can't write a book that draws on people recognising the similarity between your book and the "Harry Potter" books. It must stand on its own. So if what you create refers to the other book, you are on dangerous ground.