Englemann is one of America's great educators.
Every teacher, principal, etc. should know about his work. He advocated for "direct instruction." Basically, he was a very practical guy and advocated for whatever worked.
He believed that you had to propose a method, test the method, refine the method, and finally when you're sure it's the best possible method, then you advocate for its adoption. Our Education Establishment, he points out, does the opposite. They push for national adoption of schemes that are not fully elaborated or tested, sort of the way Obama pushed ObamaCare.
The problem nowadays is that there is so much rhetoric and propaganda on behalf of untested methods that in fact don't work. Do the people in charge not want successful methods?
This link goes to an interview with Engelmann. There is also a video of him teaching young kids many years ago.