This is a great book to learn more about differential equations. Once you have mastered some basics this should be your next stop to learn more. Its a shame that there is not time to learn these techniques in most standard classes on differential equations. Hopefully more books like this one that extend your knowledge beyond the basics will start to appear. Readers unfamiliar with this book can see what others have said here. Its always important to try to keep learning and as such here are a few solutions to exercises I've had time to look at.