Clinical Nurse Specialists (CNS) play a critical role in ensuring the implementation of high-quality evidence based care, improved patient outcomes, and reduced health care delivery costs. Professional certification is one way we distinguish our unique contributions and advanced practice nursing expertise from other advanced practice roles. This first edition of the book represents a compilation of Clinical Nurse Specialist practice knowledge contributed by respected clinicians from across the nation for certification examination preparation. The book incorporates content from the American Association of Colleges of Nursing Adult-Gerontology Clinical Nurse Specialist (AGCNS) Population Focused Competencies and the American Association of Critical Care Nurses Scope and Standards for CNS Practice. It begins with an introduction to the current AGCNS examination options, test plans and processes, as well as test taking strategies for success. The remainder of the book organizes test plan subject matter according to the three spheres of impact of CNS practice. The book includes twelve chapters presenting the overview, pathophysiology, etiology, assessment, diagnosis, treatment/management, and related pharmacology content according to each body system. It addresses the nurse and nursing practice sphere of impact. Relevant content includes age-related response to illness and adult-gerontology population specific practice standards for care and advocacy of the older adult. Emphasis is placed upon culturally competent care and safe care transitions. Nursing practice content includes consultation, collaboration, education, mentoring and communication skills. Nurse and nursing practice advocacy topics review public policy, professional practice issues, and ethical concerns. The book covers systems and systems leadership competencies of the CNS. Relevant content involves quality improvement principles, safety initiatives, financial stewardship, organizational level program development and systems change. Clinical inquiry subject matter covers evidence- based practice, research methodology, and skills for dissemination of CNS work.