(Soft question?) Sharing knowledge to students, what are the limits? I am an undergraduate lecturer. I have been bothered by this question lately.

I never and never want to claim that what I know, or even what I discover, is mine. Also, things that I discover, small or huge, more likely have been discovered before by someone, but of course I never claim that I am the first one to discover them, and I hope I will not in the future too, no matter how huge it is.

I really want to share what I know/discover to as many people as possible, especially my students, and I won't make them pay me for that, since I've been paid enough and they have paid more than how much I can imagine to the university.

What I know or discover usually is based on the books that I bought and read. The books are protected by the law of course, but then I know students can't afford them, a situation which may (usually) lead them to pirate stuffs. I make and share notes of the books, but what's the difference? Sure I put them in my own words, but still the notes are based on the books. This is just an example with books. Papers, products, etc are different, but the "sharing limit" works similar, perhaps?

The problem is, then, I am a bit afraid of this law about filesharing, copyright, IP, or something like that, which makes me think that we do have limits in order to freely educate students. I just feel that does not sound right.

What are your opinions about this situation of a teacher/lecturer? Will there always be people who "buy" knowledge/products and share them freely and in medium or slowly reaching larger scale, without claiming anything or making money of it? I feel like the limit of sharing exists and exists strongly and hard to break. :/
For actual legal advice, you should consult with your institution's legal department.

Having said that, in most countries, the legal concept of Fair Use protects you from getting in any copyright trouble for normal educational activities. There are limits to fair use (you're not allowed to photocopy a textbook and pass out copies to all your students), but making lecture notes that are based on a copyrighted textbook should be fine, as long as they are tailored to the lectures you are actually giving, and not presented as "here's my summary of the textbook so you don't have to buy it." The exact line where fair use ends is hard to define, and would be up to a judge's discretion if it got that far, but in practice, as long as you don't do anything blatant, you should be fine.