This book focuses on beam and plate elements, essential components found across various fields from automotive and aerospace engineering to civil engineering structures. It offers a comparative exploration of the fundamental equations governing thin and thick beams, as well as thin and thick plates, providing readers with a clear understanding of these foundational structural elements. By explaining the three fundamental equations of continuum mechanics--equilibrium, kinematics, and constitution--the text culminates in a unified differential equation framework, offering both beginners and experienced practitioners a fresh perspective on structural member modeling.