The National Board for Professional Teaching Standards (NBPTS) is an independent, nonprofit, nonpartisan, and nongovernmental organization that develops professional standards for early childhood, elementary, and secondary school teaching. National Board Certification signifies that a teacher or school counselor is accomplished, having met challenging professional standards as evidenced by performance-based assessments. The assessment process for National Board Certification is designed to collect standards-based evidence of accomplished practice. In all certificate areas, candidates for National Board Certification are required to complete two major components: a portfolio of classroom practice, and an assessment of content knowledge administered at a computer-based testing center. This guide is an introduction to the assessment process and eligibility requirements and provides useful information for applying for National Board Certification. The guide also contains information for those opting for "Take One!", which is a unique offering from the NBPTS that improves teaching quality by providing educators with the opportunity to reflect on their own classroom instructional practices within the context of national teaching standards, and later begin the path toward National Board candidacy, if they so choose.