Math Refresher for Scientists and Engineers, Third Edition is intended for people with technical backgrounds who would like to refresh their math skills. This book is unique because it contains in one source an overview of the essential elements of a wide range of mathematical topics that are normally found in separate texts. The first edition began with relatively simple concepts in college algebra and trigonometry and then proceeded to more advanced concepts ranging from calculus to linear algebra (including matrices) and differential equations. Numerical methods were interspersed throughout the presentation. The second edition added chapters that discussed probability and statistics. In this third edition, three new chapters with exercises and solutions have been added. The new material includes chapters on integral equations, the calculus of variations, and tensor analysis. Furthermore, the discussion of integral transforms has been expanded, a section on partial fractions has been added, and several new exercises have been included. Math Refresher for Scientists and Engineers, Third Edition is designed for the adult learner and is suitable for reference, self-review, adult education, and college review. It is especially useful for the professional who wants to understand the latest technology, the engineer who is preparing to take a professional engineering exam, or students who wish to refresh their math background. The focus of the book is on modern, practical applications and exercises rather than theory. Chapters are organized to include a review of important principles and methods. Interwoven with the review are examples, exercises, and applications. Examples are intended to clarify concepts. Exercises are designed to make you an active participant in the review process. Keeping in mind that your time is valuable, I have restricted the number of exercises to a number that should complement and supplement the text while minimizing nonessential repetition. Solutions to exercises are separated from the exercises to allow for a self-paced review. Applications provide an integration of concepts and methods from one or more sections. In many cases, they introduce you to modern topics. Applications may include material that has not yet been covered in the book, but should be familiar if you are using the book as a “refresher course.” You may wish to return to the applications after a first reading of the rest of the text. I developed much of the material in this book as course notes for continuing education courses in Denver and Houston. I would like to thank Kathy Fanchi, Cindee Calton, Chris Fanchi, and Stephanie Potter for their assistance in the development of this material. Any written comments or suggestions for improving the material are welcome.