A Doctor of Philosophy, commonly known as a PhD, is an advanced academic degree awarded to individuals who have completed extensive research in a specific field of study. This degree typically requires the completion of a dissertation, which is a substantial piece of original research that contributes new knowledge to the discipline. PhD programs are offered in various fields, including the humanities, sciences, and social sciences. Earning a PhD often prepares graduates for careers in academia, research, or specialized professional roles, allowing them to teach at universities or lead research projects in their area of expertise.