This engaging text describes the development of singular perturbations, including its history, accumulating literature, and its current status. While the approach of the text is sophisticated, the literature is accessible to a broad audience. A particularly valuable bonus are the historical remarks. These remarks are found throughout the manuscript. They demonstrate the growth of mathematical thinking on this topic by engineers and mathematicians.

The book focuses on detailing how the various methods are to be applied. These are illustrated by a  number and variety of examples. Readers are expected to have a working knowledge of elementary ordinary differential equations, including some familiarity with power series techniques, and of some advanced calculus.

Dr. O'Malley  has written a number of books on singular perturbations.  This book has developed from many of his works in the field of perturbation theory.

"This book covers a wide range of topics in the history of singularly perturbed differential equations. ? This is a lucid book written in a deceptively easy style. The book will be useful both for specialists in the theory of asymptotical methods and for experts in various fields of applications. Moreover, it may equip students and young scientists with the essential tools needed for understanding the literature and doing research in the field of asymptotical analysis and its applications." (Vladimir Sobolev, zbMATH 1336.34002, 2016)