This book is written to be an undergraduate and introductory graduate level textbook, depending on whether the more advanced topics appearing at the end of each chapter are covered.Without the advanced topics, the book is of a level readily comprehensible by junior and senior undergraduate students in science and engineering.With theadvanced topics included, thebookcan serve as the textbook for the first course in finite elements at the graduate level. The text material evolved from over 50 years of combined teaching experience by the authors of graduate and undergraduate finite element courses.