Charter school authorizing is a powerful strategy for making excellent public schools and educational opportunities available to all students. Done well, charter authorizing increases student achievement by expanding the supply of quality public schools to satisfy unmet needs--particularly by providing life-changing opportunities for students ill-served by the existing school system. Charter authorizing is complex work, requiring constant balancing of diverse and often competing interests. It is a public responsibility for authorizing institutions, as well as a highly developed profession for the individuals charged with this stewardship role. Quality authorizing requires specialized knowledge, skills, commitment, and adherence to essential professional standards in order to serve students and the public well, and achieve the purposes of state charter laws. Since 2004, the National Association of Charter School Authorizers (NACSA) has established and widely promoted such standards--the first "Principles & Standards for Quality Charter School Authorizing" and subsequent editions--to provide essential guidance to charter authorizing organizations and leaders, as well as to policymakers who seek to support quality authorizing. Because charter authorizing is a continually developing profession, these professional standards must likewise continually evolve in conjunction with the growth and complexity of the ever-growing charter school sector. "Principles & Standards for Quality Charter School Authorizing" derives from NACSA's vast experience, research, and lessons learned from working with authorizers across the nation. Accordingly, NACSA revisits and updates these Principles and Standards regularly to ensure that they address current authorizing challenges and reflect the latest lessons drawn from practice, research, and analysis. These Principles and Standards are designed primarily for authorizing institutions, and as such, they provide practical guidance to help authorizer staff and authorizer board members carry out their work as a standards-based profession rather than simply a list of tasks. For policymakers, this publication should highlight the complexity and challenges of quality authorizing--and the need for state policy to contemplate and invest adequately in authorizing to achieve a quality charter school sector. (Contains 13 endnotes.)