What makes for a great teacher? For generations, educators operated on the belief that great teaching was mostly an art, which the talented refine in the privacy of the classroom over many years of work. Think Sidney Poitier’s Mark Thackeray in To Sir with Love or Richard Dreyfuss as Glenn Holland in Mr. Holland’s Opus. The trouble with this romanticized idea is that it all depends on the individual. Yes, some educators grow and develop on their own initiative. But this model assumes that all teachers will naturally progress and negates the possibility that any educator can be coached or challenged to improve.

And because teaching happens behind closed doors, this conventional wisdom protects less-competent teachers from being assessed and, if necessary, removed. Truly awful teachers can effectively commit malpractice (like bad doctors) against thousands of unsuspecting students throughout a thirty-year career and still collect the same pay, benefits, and pensions as their most effective peers.

Right from the beginning of my job as chancellor of the New York City Department of Education, Mayor Michael Bloomberg and I realized that efforts to reinvigorate our existing teaching force would be controversial. But our endeavor was aided by the high incidence of turnover—especially in high-poverty communities—that allowed us to focus on recruiting top-quality people to fill vacated spots. The mayor raised salaries significantly and, under the terms of the contract we signed with the United Federation of Teachers in 2005, our teachers earned roughly what their peers made in more affluent suburban communities. We also partnered with Teach for America and the New Teacher Project to bring in high performers who didn’t come from the traditional education schools. In time, we would come to recruit almost one quarter of our new hires from these nontraditional sources. Many of these teachers came to us because they had heard the buzz about what we were doing.

This recruitment effort paid off handsomely. An analysis by James Wyckoff at the University of Virginia found, “There’s a really dramatic shift after 2003 to a really different workforce in New York City [schools] than there had been in place before that.” In particular, Wyckoff determined that the SAT scores and college grades of our incoming teachers were significantly improved and that we substantially closed the gap in qualifications between teachers being hired in the wealthiest and poorest schools.

But we still employed a huge number of teachers who had been in the system for years, and we had to get them on board with our program as well. Having met hundreds, if not thousands, of them, I knew that the vast majority had entered the profession filled with hope. Sadly, many had been beaten down by the bureaucracy and its top-down rules—or, worse, by dictatorial, ham-handed principals—to the point where they were just trying to survive until they qualified for pensions.

Other teachers I met just seemed complacent and showed no interest in changing. Quite a few would start their conversation with me by saying, “Chancellor Klein, I’ve been a teacher for 20 years.” Invariably this statement was followed by a recitation of the system’s ills and all the reasons why things could never get better. The clear thrust was that the teacher had seen it all. I was the new kid on the block; they’d ignored previous chancellors and would ignore me as well. When they shut the classroom door, they would do what they always did.

This kind of thinking drove me nuts. Although I knew from experience that many teachers constantly strove to improve, there were still too many who felt they were doing just fine and either needn’t or wouldn’t change. Others had just given up, and, as they told me, would have retired if possible. The absence of enthusiasm and curiosity expressed by these teachers influenced the culture of many schools. I tried to stay focused on those teachers who could be effectively engaged and kept hoping that, if we could reignite their passion and show them a world in which kids were making progress because of their efforts, they would become allies in a dramatic reformation of the classroom. But before we could start on raising the interest and quality of the existing teachers, we had to get them to agree that change was necessary, possible, and preferable to the status quo.

I decided to start a dialogue with them, both in writing and in person. My hope was that, as I invited teachers to group gatherings, brown-bag lunches, or meetings in schools, we would get to know one another as human beings. (I confess, I hoped some would say to themselves, “Hey, that Klein’s not the jerk I thought he was.”) Since it was physically impossible for me to meet 80,000 teachers face-to- face, I decided that, in addition to lots of small meetings, I’d write e-mails to them all as a group. What was to stop me? After all, I was their boss. Shouldn’t we be able to communicate?

The letter I wanted to start with began something like this:

Look, folks, let’s be honest with each other. Our school system is filled with people who came into teaching to improve the lives of kids. They didn’t come to fail. They didn’t come to make a boatload of money. They wanted to help kids.

But by and large, the system’s not working. And it’s really not working for the kids in the Bronx, Central Brooklyn, and Northern Manhattan who need it the most and don’t have the option of going someplace else to get the education they need.

The problem is not that we don’t care, and there’s no question some of our kids can be challenging to educate. It’s that we have to do things differently. Whatever else is true, we surely should not make excuses and should together take a hard look at what we’re doing—at what works and doesn’t work. Already things are improving significantly in some schools, and we can all learn from their example. None of this will be easy. It’s going to involve some growth, and some pain, and we may make mistakes. But if we do it together, with rigor and confidence, it’s the best hope we have.

The letter was never sent. As I learned, no chancellor had ever sent a substantive letter to the city’s teachers. Some may have mailed holiday greetings, or thank-you notes, but, as it turned out, the UFT did not allow me to approach teachers directly on any matter that touched on their actual work. There would be no brown-bag lunches shared in the teachers’ lounge or coffee and conversation without union supervision. These matters were all subject to collective bargaining and, therefore, I was informed (first by the union and then by my own attorney) that I couldn’t discuss them directly with the teachers.

This was a real loss. I’d had some very positive experiences with principals gathered in groups for informal sessions. Over the years, I had come to know several teachers personally and, as a result, they had a very different view of me from that held by many of their colleagues. For example, I got to know quite well a longtime physical education teacher and committed union activist who had initially e-mailed to say that, like me, he had grown up in public housing and was an avid New York sports fan. We e-mailed over the years, and although he opposed some of what we were doing, and wasn’t shy about letting me know as much, we remain friends to this day. When I stepped down, he wrote me an e-mail saying: “Sadness doesn’t really express how I feel about your decision to leave the DOE. Though many of my colleagues shouted for joy when they heard the news, I for one shed a tear for a man who really cared about children and emphasized quality education. Though all your hard work and perseverance didn’t always work out the way you had hoped, you were the maverick who led in a passionate way to change the status quo and give the DOE a direction that only a creative mind like yours could have instituted. I salute you.”

If only I could have had the chance to develop that kind of relationship with all of our teachers. Unfortunately, I never did. Several years after we started doing annual surveys as part of our accountability program, I found strong support from the principals and parents, but not the teachers. In 2010, when we surveyed my performance in four areas—resources, oversight, curriculum, and student progress—the principals gave me an average 76 percent approval and 19 percent disapproval rating; the parents gave me an average of 64 percent approval and 14 percent disapproval; and the teachers gave me an average of 39 percent approval and 46 percent disapproval. I thought the teachers’ results had to be due, at least in part, to the negative influence of the union’s constant attacks on our programs over the years and the fear and scorn instilled as a result. I just wish I had had the ability to explain to them directly what we were doing and why and to hear and address their reactions. I know we couldn’t have won them all over, but at least they would have judged us based on real information.

This post has been excerpted from Joel Klein's forthcoming book, Lessons Of Hope: How to Fix Our Schools.