When writing a book about a subject, if all your text is in your own words, and, contains only commonly known, fundamental, well established knowledge about the subject, which can all be seen in tons of resources, do you need to show any references or bibliography at all - even if you looked at other places while gathering that information, but took only the commonly established knowledge?
If you do not list any sources, can someone come to you and say "OK, you didn’t copy anything from me, but what if you looked at my book (which also has that common knowledge), since you do not list any sources"?
I am asking in terms of avoiding a legal issue. Not in terms of "citing is better for your text to be more reliable" in an academic field, etc.... This is an introductory to intermediate level book I am talking about. It is not something that claims to be at an academic level.