Correcting professors' lecture notes

I can only speak for myself, and I'm just a postdoc.

I would be indifferent if someone pointed out one or two typos; on the one hand that's helpful, on the other a bit pedantic.

However, if I received a "Word doc containing all the typos and mistakes [you] could find" in a 90 page document, I would be delighted and grateful.

_{As an aside, I'm currently working through a textbook to brush up my statistics skills. I'm trying to collect the mistakes that I stumble upon in order to send them to the author once I've finished the book, so he can correct them in the next edition.}

If you did this unsolicited, it might possibly be poorly received (though even then most people would be grateful, as long as you approached the issue in a polite manner).

However, given that the professor actually asked for this, I don't think you need to worry at all. You have done a great service, really.

I cannot speak for all professors, of course, but I'm my case I'd be delighted and I'm fairly sure that such would be the reaction of most professors.

Over the last two years I have circulated some lecture notes among my students and a few other persons, and I'm really frustrated by the lack of feedback on typos (or anything else, for that matter).