This introductory brief delves into the core concepts of Model-Based Systems Engineering (MBSE). It begins with a clear definition of MBSE, highlighting its importance in modern engineering practices. The paper then explores the fundamental pillars of MBSE, including the tools, languages, and methodologies that underpin its implementation. Additionally, it examines common views and perspectives that are consistent across various MBSE tools, providing a cohesive understanding of the field. This brief serves as a foundational guide for those looking to grasp the essentials of MBSE and its practical applications.