Once hired, many teachers are left to sink or swim. In recent years, several states have adopted controversial accountability measures, known as “value added” metrics, with a view toward winnowing out poor performers who haven’t produced student improvement on standardized tests; helping teachers hone their craft has seldom made it onto the agenda. But perhaps we’re finally ready to focus attention on the far bigger and more important question of how to attract and retain the top teachers we want.

This spring, the Obama administration announced plans to begin rating teacher-training programs. Consensus on what makes an effective teacher, however, remains elusive. Student achievement does not correlate strongly with teachers’ years of experience in the classroom (beyond the initial few) or with the caliber of their preparation—whether they have acquired certification, earned a master’s degree in education, or aced state licensing exams. Even particular personality traits, such as an extroverted willingness to ham it up in the classroom, appear irrelevant. The conundrum doesn’t daunt Elizabeth Green, a co-founder of GothamSchools (a news Web site originally devoted to covering New York City schools that has recently expanded to other cities and been rechristened Chalkbeat). Her book, Building a Better Teacher, couldn’t be better timed.

At the heart of Green’s exploration is a powerfully simple idea: that teaching is not some mystical talent but a set of best practices that can be codified and learned through extensive hands-on coaching, self-scrutiny, and collaboration. Yet her account suggests that implementing this vision may entail a bigger transformation than she quite realizes.

Green begins by profiling an array of educators who have been inspired by Deborah Ball, now the dean of the University of Michigan School of Education. In the early 1980s, she was a charismatic math teacher in East Lansing, Michigan, who developed a successful approach to teaching even very young children sophisticated concepts in math. Instead of relying on rote memorization or repetitive skills practice, Ball shepherded children through in-depth discussions of a single mathematical conjecture—for example, do two odd integers always add up to an even number? The students, steered along by their teacher, deliberated together to derive proofs for their various hypotheses. Some of the most exhilarating parts of Green’s book are the detailed descriptions of precisely how, and why, these lessons succeed. Ball helped other teachers adopt her techniques not through the usual education-school lectures, but through rigorous apprenticeship: mutual observation of lessons, followed by intensive dissection of what worked and what didn’t.

Green likens the approach to the Japanese practice of jugyokenkyu. “Lesson study” is the main form of teacher training in Japan, where colleagues routinely sit in on one another’s classes and then scrutinize a single session for hours, extracting general guidance for future instruction. Japan substantially outperforms America in math on international tests, and Green clearly believes jugyokenkyu is a crucial factor in the country’s success. She recounts how some of Ball’s ideas were adopted by the state of California in the mid-1980s but never had a chance to catch on: Teachers were expected to absorb the new policies, outlined in a state “manifesto,” and then revamp lesson plans on their own, with little or no training or ongoing support. Some educators didn’t even see the guidelines—all but ensuring the reforms would fail. The rollout of the Common Core State Standards appears to be replicating this dispiriting pattern in many places.