Recently I finished a very good book: “Building a Better Teacher,” by Elizabeth Green. Green, an education writer, has tried to distill the lessons of the last 30 or 40 years of education reform in America. As a businessperson whose passion for education has led me to many efforts to improve education in Maine — from the school board to the Governor’s Education Kitchen Cabinet to many commissions and now three different statewide business-education coalitions — reading “Building a Better Teacher” resonated deeply with my experience.

In her book, Green finds and describes the most significant figures and events in the enormous effort to improve American education initially triggered by the landmark national study in 1984, “A Nation at Risk,” decrying the state of American schools.

Legendary teachers Deborah Ball and Magdelene Lampart, both of whom got their start at Michigan State University’s Spartan Village Learning Lab in the ’70s and early ’80s, show what extraordinary teaching looks like — even as the MSU experimental approach ultimately fails. Doug Lemov, a leader of today’s charter school entrepreneurs, is shown developing the first taxonomy for good teaching practices. Researcher Eric Hanushek is credited with the first solid analytical work measuring the value of a good teacher.

Green underscores the fundamental lesson, one relearned at least once every 10 years since 1984 — nothing influences student learning more than the quality of one’s teacher. On the one hand, this hardly seems surprising. What most of us didn’t realize, until the analytic work done over the past 10 years on this issue, is how significant the impact of a good teacher is, adding an extra half to a full grade level in a given year over an average teacher.

The other big lesson from the past 40 years is just how hard it is to become a good teacher. While good teaching can be taught, it is a surprisingly daunting task and one that virtually none of America’s large teaching universities has been able to do well.

Here then is the dilemma at the heart of education reform: we know how important good teaching is, but, apart from a few isolated heroes like Deborah Ball and Magdelene Lampart, no one in America knows how to train and develop consistently good teachers. Get that: No one in America knows how to develop good teachers!

Japan, on the other hand, has been able to do so. What are the Japanese doing that we can’t? At the risk of oversimplification, it seems largely a matter of group practice and intellectual curiosity on the part of Japanese teachers. Japanese teachers work closely with their teaching colleagues, observing and critiquing each other’s classes and doing frequent debriefs of lessons to see what works and what doesn’t. In America such practices are rare.

Green’s discussion of ways to bridge this gap in American expertise includes much good material developed in the most rigorous and successful charter schools like the Academy of the Pacific Rim, KIPP (Knowledge is Power) and Achievement First. These schools have cracked the code for preparing inner city youth for success — at least for success as measured by good assessment scores and college placement. However, even these schools have begun to understand that they need to build more academic rigor and dialogue into their classes if their students are to be successful in college. Some of them have begun to turn to people like Deborah Ball for help in figuring out how to make their teachers more effective.

About the most hopeful note of Green’s book is the news that Deborah Ball and a colleague have formed a new organization called TeachingWorks and have designed a common curriculum for teacher education. The fact that previous efforts in America to build better teachers have mostly failed has not deterred Ball. In her office hangs an excerpt from Lewis Carroll’s “Alice’s Adventures in Wonderland.” In response to Alice’s lament that “there is no use in trying, one can’t believe impossible things,” the Queen replies, “I dare say you haven’t had much practice. When I was your age, I always did it for a half hour a day. Why, sometimes I’ve believed as many as six impossible things before breakfast.” Deborah has taken for her motto that last sentence: “I’ve believed as many as six impossible things before breakfast.”

With those like Deborah Ball and several other of the heroes of Building a Better Teacher, there is hope for American education. As Bob Woodbury, former chancellor of the University of Maine System and one of Maine’s great educators, often said: “Education is a long march. The joy is in the struggle.”

Ron Bancroft is a Portland businessman and member of the boards of Educate Maine and the Great Schools Partnership, both dedicated to improving teaching and learning.