Is it legal to do a public talk using the ideas you read in a book but did not write?

Question

Is it legal to do a public talk using the ideas you read in a book but did not write?

Answer

We have all learned everything we know from other sources. If you say that the United States is a republic because you read that in a history book, you do not have to cite the history book everytime you say that the US is a republic. It is improper to take credit for independent research that someone else performed, that would be improper.