I just finished reading the "early release" that is, the raw and unedited text—as the O'Reilly website describes it. It is not la lie, there are typos and minor errors, as well as several missing sections.
I am disappointed. I found this book stays halfway between theory and practice but excels in none. For instance, I found the presentations of Boltzmann machines (BM), recurrent neural networks (RNN), or Convolutional neural networks (CNN) too brief and shallow, and I had to go through other resources to understand. I don't know how helpful the DL4J examples are for the practitioner, as I did not try to run them. As technology evolves quickly, I guess this book will soon be out-of-date. I still liked the general guidance about when to use what algorithm (optimisation, weights initialization, regularisation, etc.).
If like me, you are looking for a resource to help you learn about deep learning, you may want to keep searching.