The fourth edition of this book exposes the reader to a wide array of engineering principles and their application to agriculture. It presents an array of more or less independent topics to facilitate daily assessments or quizzes, and aims to enhance the students' problem solving ability. Each chapter contains objectives, worked examples and sample problems are included at the end of each chapter. This book was first published in the late 60's by AVI. It remains relevant for post secondary classes in Agricultural Engineering Technology and Agricultural Mechanics, and secondary agriculture teachers. There is a new chapter on precision agriculture.