Does a High School Teacher need to be an expert in his domain, outside of the school Syllabus?

Is it sufficient for him to be a good professional, to teach well Pythagoras theorem, Shakespeare and Molière, and not care about the recent scientific discoveries or literary publications?

In my childhood in the “barbaric” Soviet system, I was lucky enough to have instructors who were crazy in love with their subject. They were for me the highest scientific and literary authorities, they could answer any question outside of the Syllabus.

Having taught for many years in different countries, I understand how lucky I was then.

My teachers – I miss you here, in the centre of civilization.