"Applied Mathematics in Engineering" is an edited book comprising 15 contemporaneous open-access articles focused on mathematical modelling, mathematical optimization, and fractal mathematics and their applications in modern engineering and industry. The first part covers a wide range of mathematical models for solving real-world problems in mechanical engineering, biomedicine, fluid dynamics, and other applications. The second part of the book presents various mathematical optimization methods and algorithms (e.g. topology optimization, hybrid arithmetic optimization, and isogeometric topology optimization) for solving engineering problems. The third part of the book is dedicated to the mathematics of fractals and its applications in the engineering of antennas, image compression technology, fracture mechanics, ophthalmology and more. The intended audience of this book is undergraduate and graduate students, as well as junior researchers.