I'm reading an early release of this book in O'Reilly Safari and confirm that it's worth reading.

However, if you don't get used to deep learning previously it might be worth to combine it with something more foundational about deep learning. I like the lectures by Nando de Freitas (https://www.cs.ox.ac.uk/people/nando.defreitas/machinelearni...) and a book by Ian Godfellow (http://www.deeplearningbook.org/).