I purchased this at the same time that i purchased Jordan &amp; Smith's Nonlinear Ordinary Differential Equations. In comparison, I found that whilst they don't cover exactly the same material, where they do overlap, Strogatz's book was better structured, had clearer explanations and fewer errors. There is also a series of Youtube videos of lectures given by Strogatz which covers some of the material in this book. if you have the option or you can only afford one, my recommendation would be to go with Strogatz's book.