This book reminds students in junior, senior and graduate level courses in physics, chemistry and engineering of the math they may have forgotten (or learned imperfectly) which is needed to succeed in science courses. The focus is on math actually used in physics, chemistry and engineering, and the approach to mathematics begins with 12 examples of increasing complexity, designed to hone the student's ability to think in mathematical terms and to apply quantitative methods to scientific problems. By the author's design, no problems are included in the text, to allow the students to focus on their science course assignments. It includes a highly accessible presentation of fundamental mathematical techniques needed in science and engineering courses. It makes use of proven pedagogical techniques develolped during the author's 40 years of teaching experience. It features illustrations and links to reference material on World-Wide-Web. It has coverage of fairly advanced topics, including vector and matrix algebra, partial differential equations, special functions and complex variables.