Benefits of the Adapter Pattern

Hi there:

I'm studying Design Patterns. I'd like to know more about the real benefits of the Adapter Design Pattern.

I understand the pattern, except that I don't exactly know how it can greatly benefit my designs.

I know that it allows to convert an interface into another interface to make incompatible interfaces work together.

The book I'm currently reading says that it's good because it promotes the use of interfaces. I know how interfaces are used, but what is it the author is really implying?

Rafael