This textbook is intended to provide a foundation for a one-semester introductory course on the advanced mathematical methods that form the cornerstones of the hard sciences and engineering. The work is suitable for first year graduate or advanced undergraduate students in the fields of Physics, Astronomy and Engineering. This text therefore employs a condensed narrative sufficient to prepare graduate and advanced undergraduate students for the level of mathematics expected in more advanced graduate physics courses, without too much exposition on related but non-essential material. In contrast to the two semesters traditionally devoted to mathematical methods for physicists, the material in this book has been quite distilled, making it a suitable guide for a one-semester course. The assumption is that the student, once versed in the fundamentals, can master more esoteric aspects of these topics on his or her own if and when the need arises during the course of conducting research. The book focuses on two core subjects: complex analysis and classical techniques for the solution of ordinary and partial differential equations. These topics are complemented with occasional terse reviews of other material, including linear algebra, to the extent required to ensure the book can be followed from end-to-end. This textbook is designed to provide a framework for a roughly 12 week course, with 3 weeks devoted to complex variables, a 1 week refresher on linear algebra, followed by 5 and 3 weeks devoted to ordinary and partial differential equations, respectively. This schedule leaves time for a couple of exams. The narrative is complemented with ample problem sets, including detailed guides to solving the problems.