Based on the authors' experience teaching introductory numerical methods and optimization courses, this book covers numerical methods for Industrial and Systems Engineering and Operations Research. It combines the materials from introductory numerical methods and introductory optimization courses into a single text, which, on the one hand, enriches a "standard" numerical methods syllabus with optional chapters on numerical optimization, and, on the other hand, provides a valuable numerical methods background for students taking an introductory optimization course.