Book excerpt: The book explores the technology used in proportional valves. The book also describes the construction of electro-hydraulic proportional valve systems, the details of various types of control elements, and the characteristics of proportional valve systems. A fluid power professional should possess exceptional knowledge about proportional valves for his/her continuing professional development and career advancement. A faculty or a student in an engineering institution must acquire the knowledge of proportional valves to upgrade his/her knowledge. As the knowledge and skill of the reader improve, professional life is undoubtedly going to be more outstanding and comfortable.The book has been written by a professional trainer who has vast experience in the fluid power area and trained thousands of professionals and students, over 25 years. If you are looking for a more in-depth knowledge into fluid power, then this book is a valuable resource that will assist you in your quest for professional development.