What is the international trade?

Textbooks have copyrights. What are they protected from since textbooks are really just facts and knowledge? Say in International Economics, you can't really copyright a diagram illustrating gains of trade from Ricardo's comparative advantage, can you?

• I want to write a guide book for A levels Economics. The objective of the book is not to be a replacement for textbooks, but to guide students on where the extra knowledge that they would need to achieve an A in essay writing could be found. I want to be clear on what I can do and what I can't. I want to thank you in advance for reading my detailed and specific questions. I am publishing the guide book to help students so it's going to be pretty much very little profit, especially in the very small country I am in and considering that I probably can't make as much sales as I would like, hence I probably can't afford any lawyer's consultation fees. So I would be really grateful if someone could help me out a little here. Many thanks for your time.   (1) There are really sometimes not many ways you could define something differently. Take  international trade" as an example: International trade is the buying and selling of goods and services across international boundaries. It's nearly impossible to define it anyway else and still be accurate; words and phrases like "buying and selling", "goods and services", and "across international boundaries" have to be there! So inevitably, my definition will look super similar, if not identical to at least one textbook out there! Am I infringing on the copyright of that textbook?   (2) Some things have only a couple of standard ways to illustrate as can be seen by how most textbooks uses pretty much the same method. For example, I would need to use a diagram and illustrate the gains of trade based on Ricardo's Theory of Comparative Advantage, and pretty much, there's only a couple of ways to do that and pretty much every single textbooks used them, so definitely not incredibly creative. If I were to use that, but change the figures and perhaps names of the countries used in their examples (even then, I could still have coincidentally "reproduced" someone's else example in some textbooks I probably never read before}, am I still infringing on their copyrights? I mean, these stuff seems pretty standard, can they sue me since I am using it to publish a guidebook which I would sell?   (3) The intention of the guidebook is not to be a textbook replacement. I don't want to write a textbook. This guidebook is more for students who already knew their basics from whichever textbooks they are using but needed some extra knowledge and information that are usually beyond their scope to impress markers that they read widely and well beyond. Thus, I would include a lot of information, some of them from more recent research papers or books published. I won't be writing every single thing that those books have, just one or two short points, and maybe some elaborations done by myself, then a final sentence to refer them to the respective books, authors and which pages to read more about it.   For example, I would like to provide some recent knowledge that's not in orthodox mainstream about downsides to international trade. I will explain the points briefly and then point them to where they could read more about it. Say, I might share the idea that perhaps developed countries got to where they are today through protectionism. This is essentially Ha-Joon Chang's idea in his book "Kicking away the ladder". Since this a non-fiction, this "idea" he arrived (i.e. that developed countries could have arrived at where they are today through protectionism and their strong avocation of free trade to today's developing countries as the way panacea to poverty is hypocrisy) will essentially be new economic knowledge that he discovered and is backed by historical data he provided which are facts! So if I were to include them in, am I infringing on his copyright since facts and knowledge cannot be copyrighted? I would be re-writing as much as I could when elaborating his ideas and probably won't be using his examples or the exact way he used to explain his idea.

• Answer:

  Copyright does not protect against repeating facts.  Copyright can protect something as basic as a reference (e.g. a phone book), but only the organization of the reference.  So, you can fill a reference with facts.  Readers can repeat those facts in other works.  They just cannot copy your text verbatim.