Mr. Doctor from the House of Everything in Another World

Then he traveled to a world of swords and magic. There is no system, no cheats, no chirping system. There is only a textbook that disappears and appears in my mind. Good news: He understands water treatment and pollution control. He has taken many practical professional courses and can write papers. Bad news: There are magicians in this world. Even worse news: He's skipping some classes.