Teachers cannot teach what they do not know. This country has tolerated a weak licensing system for prospective teachers for decades. This weak system has been accompanied by an increasingly emptier curriculum for most students, depriving them of the knowledge and skills needed for self-government. An Empty Curriculum: How Teacher Licensure Tests Lead to Empty Student Minds makes the case that the complete revision of the licensing system for prospective and veteran teachers in Massachusetts in 2000 and the construction of new or more demanding teacher licensing tests contributed significantly to the Massachusetts "education miracle." That "miracle" consisted of enduring gains in achievement for students in all demographic groups and in all regional vocational/technical high schools since 2005--gains confirmed by tests independent of Massachusetts policy makers. The immediate purpose of this book is to explain what Massachusetts did in 2000 to strengthen its teacher licensing and re-licensing system to ensure that all teachers could teach to relatively strong K-12 standards. Its larger purpose is to suggest that development of strong academic standards in all major subjects should be followed by complete revision of a state's teacher licensing system, not, as has been the case for several decades, the development of K-12 student tests--if this country wants to strengthen public education.