This edited volume offers a foundational exploration of the STEM microcredential landscape. Bringing together educators, researchers, policymakers, and industry leaders, the chapters in this volume demonstrate the flexibility and targeted nature of STEM microcredentials, meeting the demands of a rapidly evolving job market through competency-based learning. It examines the intricate relationships between learners, higher education institutions, and the workforce through sections focused on an overview, frameworks, and topic studies. By delving into the foundational theories and current practices, this volume sets the stage for the practical case studies and future-oriented discussions presented in Volume II, providing a comprehensive look at the STEM microcredential landscape.