This book covers the applications of Mathematics in Chemical Engineering and other fields. Theoretical part is summarized in the beginning of the chapters, so that the reader does not have to refer other books of Mathematics. The applications are covered step-by-step starting from easy ones to tough problems. All background and requisite materials are included for readers’ convenience. The various topics included are: Elementary problems, Formation of equations, Ordinary differential equations, Solutions by series methods, Partial differentiation, Partial differential equations, Numerical solutions, Statistical methods, Optimization problems, Laplace transforms and solutions, other mathematical methods. The book is useful for B.Tech (Chemical Engineering) students, pharmacy students and for practising engineers. In transport phenomena subject, sometimes the equations are not fully solved. In those cases, this book will be of immense help in seeing the solutions. In subjects like fluid mechanics, heat transfer and mass transfer, the contents of this book will be useful to understand the solutions.