This book reviews math topics relevant to non-mathematics students and scientists, which they may not have seen or studied for a while. These math issues can range from reading mathematical symbols to using complex numbers, dealing with equations involved in calculating medication equivalents, the General Linear Model (GLM) used in neuroimaging analysis, finding the minimum of a function, independent component analysis, or filtering approaches. Almost every student or scientist will, at some point, run into mathematical formulas or ideas in scientific papers that may be hard to understand, given that formal math education may have been some years ago. In this book, we will explain the theory behind many of these mathematical ideas and expressions and provide readers with the tools to better understand them. We will revisit high school mathematics and extend and relate this to the mathematics used in various fields.