This textbook is intended to be used by the senior engineering undergraduate and the graduate student. Nowadays, the finite element method has become one of the most widely used techniques in all the engineering fields, including aerospace engineering, mechanical engineering, biomedical engineering, etc. To unveil the FE technique, the textbook provides a detailed description of the finite element method, starting from the most important basic theoretical basis, e.g., the Galerkin method, the variational principle, followed by the detailed description of the various types of finite elements, including the bar, the beam, the triangular, the rectangular, the 3D elements. The primary aim of the textbook is to provide a comprehensive description of the FE solutions using different types of elements. Therefore, the properties of different elements and the solution discrepancies caused by using different elements are highlighted in the book. Thus, the textbook is very helpful for engineers to understand the behaviours of different types of elements. Additionally, the textbook can help the students and engineers write FE codes based on the theories presented in the book. Furthermore, the textbook can serve as the basis for some advanced computational mechanics courses, such as the nonlinear finite element method.