Head First Design Patterns is a light weight introduction to object oriented design patterns. It approaches each design patterns with different perspectives and compares them to each others.
However, just like another book in the Head First series, this book contains tedious exercises and not-so-funny cartoons which I would normally skip through. Those parts make up 40% of the book which is quite annoying.
Nevertheless, if these don’t bother you, it will still serve your needs to dive into the world of design patterns.
Edit: Some readers misunderstood me. I don’t really hate the book, but it would be much better if the editor can improve the exercises and the way they the story. Other than that, I still think HFDP is a great book that can guide you into design patterns step by step.